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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2016	Feb. 28, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Trading Symbol	CBIO
Entity Registrant Name	CATALYST BIOSCIENCES, INC.
Entity Central Index Key	0001124105
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		1,000,036
Entity Public Float			$ 12,081,112

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 10,264	$ 29,096
Short-term investments	6,800	3,402
Restricted cash	19,468	33,794
Deposits		133
Accounts receivable	31	492
Prepaid and other current assets	958	1,781
Total current assets	37,521	68,698
Restricted cash, noncurrent	125	125
Property and equipment, net	444	698
Total assets	38,090	69,521
Current liabilities:
Accounts payable	837	939
Accrued compensation	596	926
Other accrued liabilities	805	535
Deferred revenue, current portion	283	438
Deferred rent, current portion	41	19
Redeemable convertible notes	19,403	33,743
Derivative liability		1,156
Total current liabilities	21,965	37,756
Deferred revenue, noncurrent portion	47	292
Deferred rent, noncurrent portion	7	48
Total liabilities	22,019	38,096
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000,000 shares and no shares authorized and outstanding at both December 31, 2016 and December 31, 2015
Common stock, $0.001 par value, 100,000,000 shares authorized; 801,756 and 762,005 shares issued and outstanding at December 31, 2016 and December 31, 2015	1	1
Additional paid-in capital	164,053	162,460
Accumulated other comprehensive income (loss)	(1)	1
Accumulated deficit	(147,982)	(131,037)
Total stockholders’ equity	16,071	31,425
Total liabilities and stockholders’ equity	$ 38,090	$ 69,521

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	801,756	762,005
Common stock, shares outstanding	801,756	762,005

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Contract revenue	$ 399	$ 1,750
Operating expenses:
Research and development	11,555	5,958
General and administrative	9,262	9,594
Total operating expenses	20,817	15,552
Loss from operations	(20,418)	(13,802)
Interest and other income, net	3,473	518
Interest expense		(1,478)
Net loss	$ (16,945)	$ (14,762)
Net loss per common share, basic and diluted	$ (21.75)	$ (49.99)
Shares used to compute net loss per common share, basic and diluted	779,166	295,272

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (16,945)	$ (14,762)
Other comprehensive income (loss):
Unrealized (loss) gain on available-for-sale securities	(2)	1
Total comprehensive loss	$ (16,947)	$ (14,761)

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Convertible Preferred Stock	Convertible Preferred Stock Series F Convertible Preferred Stock	Common Stock	Common Stock Redeemable Convertible Preferred Stock	Additional Paid-In Capital	Additional Paid-In Capital Redeemable Convertible Preferred Stock	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance (in shares) at Dec. 31, 2014			87,405,011
Balance at Dec. 31, 2014			$ 108,877
Balance at Dec. 31, 2014	$ (109,352)						$ 6,923			$ (116,275)
Balance (in shares) at Dec. 31, 2014					24,729
Stock based compensation expense associated with vesting of stock awards	326						326
Stock options exercised for cash, value	$ 13						13
Stock options exercised for cash, shares	254				254
Conversion of convertible securities, value	$ 117,647	$ 241	$ (117,647)	$ 1,511	$ 1		117,646	$ 241
Conversion of convertible securities, shares			(94,705,256)	1,511,723	409,877	1,720
Issuance of stock, value			$ 7,259
Issuance of stock, shares			5,788,522
Conversion of preferred stock warrants to common stock warrants in connection with merger	774						774
Issuance of common stock in connection with reverse merger, value	36,537						36,537
Issuance of common stock in connection with reverse merger, shares					325,425
Unrealized (loss) gain on available-for-sale securities	1								$ 1
Net loss	(14,762)									(14,762)
Balance at Dec. 31, 2015	31,425				$ 1		162,460		1	(131,037)
Balance (in shares) at Dec. 31, 2015					762,005
Stock based compensation expense associated with vesting of stock awards	635						635
Conversion of convertible securities, value		$ 1						$ 1
Conversion of convertible securities, shares						8
Issuance of stock, value	957						957
Issuance of stock, shares					39,743
Unrealized (loss) gain on available-for-sale securities	(2)								(2)
Net loss	(16,945)									(16,945)
Balance at Dec. 31, 2016	$ 16,071				$ 1		$ 164,053		$ (1)	$ (147,982)
Balance (in shares) at Dec. 31, 2016					801,756

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Series F Convertible Preferred Stock
Net of issuance costs	$ 96

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net loss	$ (16,945,000)	$ (14,762,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	635,000	326,000
Depreciation and amortization	389,000	470,000
Non-cash interest expense		1,478,000
(Gain) loss on disposal of fixed assets	(557,000)	15,000
Gain on sale of NNR assets	(1,674,000)
Gain on extinguishment of redeemable convertible notes	(99,000)	(52,000)
Change in fair value of warrant liability		(91,000)
Change in fair value of derivative liability	(1,057,000)	(242,000)
Changes in operating assets and liabilities:
Accounts receivable	461,000	(79,000)
Prepaid and other current assets	956,000	(1,350,000)
Accounts payable	(102,000)	(4,273,000)
Accrued compensation and other accrued liabilities	(60,000)	1,150,000
Deferred rent	(19,000)	41,000
Deferred revenue	(400,000)	(1,749,000)
Net cash flows used in operating activities	(18,472,000)	(19,118,000)
Investing Activities
Proceeds from the reverse merger		23,931,000
Proceeds from maturities of investments	10,002,000	13,823,000
Purchase of investments	(13,401,000)
Proceeds from sale of NNR assets	1,674,000
Change in restricted cash	(5,000)	(125,000)
Proceeds from sale of property and equipment	890,000	0
Purchases of property and equipment	(468,000)	(272,000)
Net cash flows (used in) provided by investing activities	(1,308,000)	37,357,000
Financing Activities
Release of restricted cash due to conversion and redemption of redeemable convertible notes	14,330,000	3,255,000
Payments for the redemption of redeemable convertible notes	(14,340,000)	(3,020,000)
Proceeds from issuance of common stock, net of issuance costs	958,000
Proceeds from issuance of convertible preferred stock, net of issuance costs		7,259,000
Proceeds from issuance of convertible notes to related parties		1,888,000
Repurchase of common stock in connection with equity award assumed		(82,000)
Proceeds from the exercise of common stock options		13,000
Net cash flows provided by financing activities	948,000	9,313,000
Net (decrease) increase in cash and cash equivalents	(18,832,000)	27,552,000
Cash and cash equivalents at beginning of year	29,096,000	1,544,000
Cash and equivalents at end of year	10,264,000	29,096,000
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Investment securities received from the reverse merger		17,223,000
Redeemable convertible notes assumed upon reverse merger		37,073,000
Unrealized Gain (Loss) on investments	$ (2,000)	1,000
Embedded derivative related to redeemable convertible notes		1,455,000
Common stock
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Conversion of convertible notes to stock		241,000
Series F convertible preferred stock
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Conversion of convertible notes to stock		1,511,000
Conversion of preferred stock warrant liabilities to equity upon reverse merger
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Conversion of stock		774,000
Conversion of preferred stock and warrant liabilities to equity upon reverse merger
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Conversion of stock		$ 117,647,000

Nature of Operations

12 Months Ended

Dec. 31, 2016

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of Operations

1.	Nature of Operations

Catalyst Biosciences, Inc. (the “Company” or “Catalyst”), is a clinical-stage biotechnology company focused on developing novel medicines to address hematology indications, including the treatment of hemophilia. Its facilities are in South San Francisco, California and it operates in one segment.

On February 10, 2017, the Company effected a reverse stock split of its common stock at a ratio of 1-for-15 (“2017 Reverse Stock Split”). The 2017 Reverse Stock Split was approved by the Company’s stockholders at a special meeting of stockholders held on February 2, 2017. As a result of the 2017 Reverse Stock Split, each 15 pre-split shares of common stock outstanding were automatically combined into one new share of common stock, and the number of outstanding shares of common stock on the date of the split was reduced from approximately 13.0 million shares to approximately 868,000 shares. Unless otherwise specified, all share and per share amounts in these notes and the accompanying consolidated financial statements are reported on a post-stock split basis for all periods presented.

Reverse Merger

Prior to August 20, 2015, the name of the Company was Targacept, Inc. On August 20, 2015, Targacept completed its business combination with Catalyst Bio, Inc. (“Catalyst Bio”) in accordance with the terms of an Agreement and Plan of Merger, dated as of March 5, 2015, as amended on May 6 and May 13, 2015, by and among Targacept, Talos Merger Sub, Inc. (“Merger Sub”) and Catalyst Bio, pursuant to which Merger Sub merged with and into Catalyst Bio, with Catalyst Bio surviving as a wholly-owned subsidiary of Targacept (the “Merger”). Also on August 20, 2015, in connection with, and prior to the completion of, the Merger, Targacept effected a 1-for-7 reverse stock split of its common stock (the “Reverse Stock Split”) and changed its name from Targacept, Inc. to Catalyst Biosciences, Inc. Following the completion of the Merger, the business conducted by the Company became primarily the business conducted by Catalyst Bio described in the paragraph above. We refer in this Annual Report on Form 10-K to the business combination as the “Merger,” to the Company prior to the Merger as “Targacept” and to our subsidiary as “Catalyst Bio,” and discussions of historical results reflect the results of Catalyst Bio prior to the completion of the Merger and do not include the historical results of Targacept prior to the completion of the Merger.

On August 19, 2015, prior to and in connection with the Merger, the Company paid a dividend to the Targacept holders consisting of cash and non-interest bearing redeemable convertible notes (the “Pre-Closing Dividend”), see Note 9 for further detail. In connection with the Pre-Closing Dividend and the reverse-stock split, the Company adjusted the number of shares subject to each outstanding option to purchase its common stock. On August 20, 2015, upon the completion of the Merger, the Company issued shares of its common stock to Catalyst Bio stockholders in exchange for each share of Catalyst Bio common stock outstanding immediately prior to the Merger and assumed all the outstanding options and warrants of Catalyst Bio, with such options and warrants henceforth representing the right to purchase a number of shares of the Company’s common stock. All preferred stock and warrants were converted to common stock and warrants to purchase common stock upon the closing of the Merger.

Liquidity

We had a net loss of $16.9 million for the year ended December 31, 2016 and an accumulated deficit of $148.0 million as of December 31, 2016 and expect to continue to incur losses for the next several years. As of December 31, 2016, we had $17.1 million in cash, cash equivalents and short-term investments, a $16.9 million net loss and $18.5 million cash used in operations. Management believes that the currently available resources, including cash, cash equivalents and short term investments as well as the cash raised from the sale of common stock in January 2017 (see Note 14) and availability under our Capital on Demand Sales Agreement (See Note 14), will provide sufficient funds to enable us to meet its operating plan for at least the next twelve months from the date of this filing.

However, if our anticipated operating results are not achieved in future periods, management believes that planned expenditures can be reduced to extend the time period over which the then-available resources would be able to fund our operations. We plan to continue to fund losses from operations and capital funding needs through future equity and/or debt financings, as well as potential additional asset sales, licensing transactions, collaborations or strategic partnerships with other companies. The sale of additional equity or convertible debt could result in additional dilution to our stockholders. The incurrence of indebtedness would result in debt service obligations and could result in operating and financing covenants that would restrict our operations. We can provide no assurance that financing will be available in the amounts we need or on terms acceptable to us, if at all. If we are not able to secure adequate additional funding we may be forced to delay, make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, and/or suspend or curtail planned programs. Any of these actions could materially harm our business.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements include the accounts of the Company and its subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation. The Company’s consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”).

Use of Estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, convertible notes and related warrants up to the date of conversion, common stock and stock-based compensation. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company invests its excess cash in bank deposits, consisting primarily of money market mutual funds. The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents.

Restricted Cash

Restricted cash consists of certain checking, money market and certificate of deposit accounts that are: (i) pledged to or held in a segregated escrow account by the Company’s correspondent banks for the benefit of the holders of the redeemable convertible notes in order to facilitate the payment of the redeemable convertible notes upon redemption or at maturity as discussed in Note 3 - Fair Value Measurements or (ii) pledged as collateral for the Company’s corporate credit card and deposit for its facility lease.

Fair Value of Financial Instruments

The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.

The fair value hierarchy requires that an entity maximize the use of observable inputs when estimating fair value. The fair value hierarchy includes the following three-level classification which is based on the market observability of the inputs used for estimating the fair value of the assets or liabilities being measured:

Level 1 – Quoted prices in active markets for identical assets or liabilities.

Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability.

Fair value accounting is applied for all financial assets and liabilities and non-financial assets and liabilities that are recognized at fair value in the financial statements on a recurring basis (at least annually).

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets, which are three years for computer equipment and software, and three to seven years for laboratory and office equipment, furniture and leasehold improvements.

Investments

All investments have been classified as “available-for-sale” and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and reevaluates such designation as of each balance sheet date. Unrealized gains and losses are excluded from earnings and are reported as a component of comprehensive loss. Realized gains and losses and declines in fair value determined to be other-than-temporary, if any, on available-for-sale securities are included in interest and other income. The cost of securities sold is based on the specific-identification method. Interest on short-term investments is included in interest and other income.

Derivative Liability

The embedded redemption feature in the redeemable convertible notes, which are convertible into shares of the Company’s common stock, is accounted for as a derivative liability at its estimated fair value. The derivative is subject to remeasurement at the end of each reporting period, with changes in fair value recognized as a component of interest and other income, in the consolidated statements of operations. The Company will continue to adjust the liability for changes in fair value until the earlier of the conversion, redemption or maturity of the redeemable convertible notes, as of December 31, 2016 the fair value was immaterial.

Revenue Recognition

The Company enters into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments, full time equivalent based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations.

Revenue is recognized when the four basic criteria for revenue recognition are met: (1) persuasive evidence of an arrangement exists; (2) transfer of technology has been completed or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured.

Revenue recognition for multiple element revenue arrangements will have deliverables associated with the arrangement divided into separate units of accounting provided that (i) a delivered item has value to the customer on a standalone basis and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the control of the vendor. As a biotechnology company with unique and specialized technological undelivered performance obligations associated with its collaborations, the Company’s multiple element arrangements most often involve deliverables and consideration that do not meet the criteria for having stand-alone value.

Deliverables and performance obligations are accounted for under a single unit of accounting when they do not have stand-alone value and the related consideration is recognized as revenue over the estimated period of when the performance obligations are to be performed. The revenue is recognized on a proportional performance basis when the levels of the performance obligations under an arrangement can be reasonably estimated and on a straight-line basis when they cannot.

The Company’s collaboration agreements entitle it to additional payments upon the achievement of performance-based milestones related to product development, regulatory actions and commercial events in certain geographic areas. Milestones that are not deemed probable or that are tied to counter-party performance are not included in the Company’s revenue until the performance conditions are met. If a collaborative agreement milestone is deemed to be substantive, as defined in the accounting rules, the Company is permitted to recognize revenue related to the milestone payment in its entirety.

In the event milestones are deemed non-substantive, the Company recognizes, and defers if applicable, payments for the achievement of such non-substantive milestones over the estimated period of performance applicable to each collaborative agreement using the proportional performance method or on a straight-line basis, as appropriate.

Amounts received under a collaborative agreement prior to satisfying revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Deferred revenue is recorded on the Company’s consolidated balance sheet as short-term or long-term based on its best estimate as to when such revenue will be recognized. Short-term deferred revenue consists of amounts that the Company expects to recognize as revenue in the next 12 months. Amounts that the Company expects will not be recognized prior to the next 12 months are classified as long-term deferred revenue.

The Company’s performance obligations under its collaboration arrangements also consist of participation on steering committees and the performance of other research and development and business development services. The timing for satisfying these performance obligations can be difficult to estimate and can be subject to change over the course of these agreements. A change in the estimated timing for satisfying the Company’s performance obligations could change the timing and amount of revenue that the Company recognizes and records in future periods.

Research and Development Expenses

Research and development costs are expensed as incurred. Research and development costs consist of payroll and other personnel-related expenses, laboratory supplies and reagents, contract research and development services, and consulting costs, as well as allocations of facilities and other overhead costs. Under the Company’s collaboration agreements, certain specific expenditures are reimbursed by third parties. During the years ended December 31, 2016 and 2015, the Company recorded a reduction to research and development expenses of $0.1 million and $0.9 million, respectively related to these reimbursements.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents, investments and accounts receivable. The Company’s investment policy restricts cash investments to high credit quality, investment grade investments. The Company believes that it has established guidelines for investment of its excess cash that maintain safety and liquidity through its policies on diversification and investment maturity. The Company is exposed to credit risk in the event of default by the institutions holding the cash and cash equivalents to the extent of the amounts recorded on the balance sheets

The Company’s accounts receivable at December 31, 2016 was $0.01 million, due from ISU Abxis. The Company has incurred no credit losses to date. The Company does not require collateral from its collaboration partners.

Income Taxes

Income taxes are computed using the liability method. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse.

The Company follows the authoritative guidance on accounting for uncertainty in income taxes. This guidance prescribes a more-likely-than-not threshold for financial statement recognition and measurement of a tax position taken in the Company’s income tax returns. This interpretation also provides guidance on accounting for interest and penalties and associated with tax positions, accounting for income taxes in interim periods and income tax disclosures.

The Company’s policy is to include penalties and interest expense related to income taxes as a component of other expense and interest expense, respectively, as necessary.

Stock-Based Compensation

The Company measures the cost of employee and director services received in exchange for an award of equity instruments based on the fair value of the award on the date of grant and recognizes the related expense over the period during which the employee or director is required to provide service in exchange for the award on a straight-line basis.

The Company uses the Black-Scholes option-pricing valuation model to estimate the grant-date fair value of stock-based awards. The determination of fair value for stock-based awards on the date of grant using an option-pricing model requires management to make certain assumptions regarding a number of variables. The Company records stock-based compensation as compensation expense, net of the estimated impact of forfeited awards. The Company applies a forfeiture rate to stock-based compensation expense using historical data to estimate pre-vesting option forfeitures. The Company estimates forfeitures at the time of grant, and revises those estimates in subsequent periods if actual forfeitures differ materially from those original estimates. As such, the Company recognizes stock-based compensation expense only for those stock-based awards that are expected to vest, over their requisite service period, based on the vesting provisions of the individual grants.

For nonemployee stock-based awards, the measurement date on which the fair value of the stock-based award is calculated is equal to the earlier of (i) the date at which a commitment for performance by the counterparty to earn the equity instrument is reached or (ii) the date at which the counterparty’s performance is complete. The Company recognizes stock-based compensation expense for the fair value-based measurement of the nonemployee awards using the Black Scholes option-pricing valuation model and the awards are typically subject to periodic re-measurement over the period that services are rendered.

Deferred Rent

The Company’s facilities lease agreement provides for an escalation of rent payments each year. The Company records rent expense on a straight-line basis over the term of the lease. The difference between the amount of expense recognized and the amount of rent paid is recorded as deferred rent in the accompanying consolidated balance sheets.

Net Loss per Share

Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is the same as basic net loss per share, since the effects of potentially dilutive securities are antidilutive given the net loss of the Company for all periods presented.

Fair Value Measurements

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value Measurements

3.	Fair Value Measurements

For a description of the fair value hierarchy and our fair value methodology, see “Note 2 – Summary of Significant Accounting Policies”. As of December 31, 2016 and 2015, the Company’s highly liquid money market funds included within cash equivalents, U.S. government agency securities and restricted cash including deposit in an escrow account are financial assets that are valued using Level 1 inputs. The Company classifies its municipal bonds and corporate notes as Level 2. Level 2 inputs for the valuations are limited to quoted prices for similar assets or liabilities in active markets and inputs other than quoted prices that are observable for the asset or liability. There were no transfers in or out of Level 1 and Level 2 during the periods presented.

Liabilities that are measured at fair value consist of the derivative liability and the warrant for convertible preferred stock that utilize Level 3 inputs. There were no transfers in or out of Level 3 during the periods presented.

The following tables present the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 and 2015 (in thousands):

	December 31, 2016
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	10,156		—		—	$	10,156
Restricted cash (money market funds)⁽²⁾		19,593		—		—		19,593
U.S. government agency securities⁽³⁾		6,800		—		—		6,800
Total financial assets	$	36,549	$	—	$	—	$	36,549
Financial liabilities:
Derivative liability⁽⁴⁾		—		—		—	$	—
Total financial liabilities	$	—	$	—	$	—	$	—

(1)	Included in Cash and Cash Equivalents on accompanying consolidated balance sheets.

(2)	$19.4 million of restricted cash serves as full collateral for the redeemable convertible notes and $125,000 of restricted cash serves as collateral for the Company’s corporate credit card and deposit for its facility lease.

(3)	Included in Short Term Investments on accompanying consolidated balance sheets.

	December 31, 2015
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	28,927	$	—	$	—	$	28,927
Restricted cash (money market funds)⁽²⁾		33,919		—		—		33,919
Municipal bonds⁽³⁾		—		296		—		296
Corporate notes⁽³⁾		—		3,106		—		3,106
Total financial assets	$	62,846	$	3,402	$	—	$	66,248
Financial liabilities:
Derivative liability⁽⁴⁾	$	—	$	—	$	1,156	$	1,156
Total financial liabilities	$	—	$	—	$	1,156	$	1,156

(1)	Included in Cash and Cash Equivalents on accompanying consolidated balance sheets.

(2)	$33.8 million of restricted cash serves as full collateral for the redeemable convertible notes and $125,000 of restricted cash serves as collateral for the Company’s corporate credit card and deposit for its facility lease.

(3)	Included in Short Term Investments on accompanying consolidated balance sheets.

(4)

The fair value of the derivative liability is measured using the Black-Scholes option-pricing valuation model. Inputs used to determine the estimated fair value of the conversion option include the fair value of the underlying common stock at the valuation measurement date, the remaining contractual term of the conversion option, risk-free interest rates, expected dividends and expected volatility of the price of the underlying common stock. In addition, the Company estimated the convertible redeemable note exchange rate based on an analysis of its actual exchange of notes for cash redemption or exchange of notes for conversion to common stock. See Note 9 - Redeemable Convertible Notes for further detail.

The following table presents the activity for the derivative liability measured at estimated fair value using unobservable inputs for the year ended December 31, 2016 (in thousands):

	Derivative Liability
Balance as of December 31, 2015	$	1,156
Change in fair value included in interest and other income		(1,057	)
Gain on extinguishment of redeemable convertible notes		(99	)
Balance as of December 31, 2016	$	—

As of December 31, 2016 the fair value of the derivative liability was immaterial. The estimated reporting date fair value-based measurement of the derivative liability was calculated using the Black-Scholes valuation model, based on the following weighted-average assumptions for the year ended December 31, 2016:

	As of December 31,
	2016			2015
Expected term	1.01			2.00
Expected volatility		80.6	%		81.7	%
Risk-free interest rate		1.20	%		1.06	%
Expected dividend yield		0	%		0	%

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Financial Instruments

12 Months Ended

Dec. 31, 2016

Investments All Other Investments [Abstract]

Financial Instruments

4.	Financial Instruments

Cash equivalents, restricted cash and short-term and long-term investments, all of which are classified as available-for-sale securities, consisted of the following (in thousands):

December 31, 2016	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Money market funds	$	10,156	$	—	$	—		$	10,156
Restricted cash (money market funds)		19,593		—		—			19,593
U.S. government agency securities		6,802		—		(2	)		6,800
Total financial assets	$	36,551	$	—	$	(2	)	$	36,549
Classified as:
Cash and cash equivalents								$	10,156
Restricted cash (money market funds)									19,593
Short-term investments									6,800
								$	36,549

December 31, 2015	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Money market funds	$	28,927	$	—	$	—		$	28,927
Restricted cash (money market funds)		33,919		—		—			33,919
Municipal bonds		295		1		—			296
Corporate notes		3,106		1		(1	)		3,106
Total financial assets	$	66,247	$	2	$	(1	)	$	66,248
Classified as:
Cash and cash equivalents								$	28,927
Restricted cash (money market funds)									33,919
Short-term investments									3,402
								$	66,248

As of December 31, 2016, the remaining contractual maturities of available-for-sale securities was less than one year. There have been no significant realized gains or losses on available-for-sale securities for the periods presented. The carrying amounts of cash, accounts receivable and accounts payable approximate fair values due to the short-term maturity of these instruments.

Restructuring Actions

12 Months Ended

Dec. 31, 2016

Restructuring And Related Activities [Abstract]

Restructuring Actions

5.	Restructuring Actions

In September 2016, the Company announced a reduction in workforce of 10 employees, or approximately 50% of the company’s workforce, consistent with a revised strategic plan to reallocate our resources to our hemostasis programs, including our highly potent next-generation Factor VIIa variant marzeptacog alfa (activated), and our highly potent next-generation Factor IX CB 2679d/ISU304. The principal objective of the 2016 Restructuring was to enable the Company to focus its efforts and resources on advancing marzeptacog alfa (activated), and CB 2679d/ISU304, through Phase 2/3 and Phase 1/2 clinical trials, respectively.

For the years ended December 31, 2016 and 2015, the Company recorded restructuring charges of $1.0 million and $0, respectively, in R&D expense, due primarily to $0.9 million employee severance and benefits, and $0.1 million for legal and facility expenses. The restructuring balance was fully paid by December 31, 2016. In connection with the restructuring, the Company received proceeds on the sale of equipment of $0.9 million resulting in a gain of $0.6 million which is reported in interest and other income. There were no such proceeds during 2015.

Property and Equipment

12 Months Ended

Dec. 31, 2016

Property Plant And Equipment [Abstract]

Property and Equipment

6.	Property and Equipment

Property and equipment consisted of the following (in thousands):

	Year Ended December 31,
	2016			2015
Laboratory and office equipment	$	—		$	4,458
Furniture		317			321
Leasehold improvements		1,613			1,591
Computer equipment		230			21
Software		144			8
		2,304			6,399
Less accumulated depreciation and amortization		(1,860	)		(5,701	)
Property and equipment, net	$	444		$	698

Property and equipment depreciation and amortization expense for the years ended December 31, 2016 and 2015 was $0.4 million and $0.5 million, respectively.

In connection with the Restructuring, the amount recorded as a restructuring charge for asset impairment, as presented in “Note 5 -Restructuring Actions,” was net of the gain on the sale of such assets. In 2016, the net gain on the sale of equipment was $0.6 million. There were no such gains in 2015.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2016

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

7. Commitments and Contingencies

Operating Leases

The Company leases office and research space under operating leases that expire in February 2018. As a result of the Restructuring, we exited certain facilities in South San Francisco.

The Company’s rental expense under its operating leases was $0.7 million in each of the years ended December 31, 2016 and 2015.

Future minimum lease payments under all non-cancelable operating leases at December 31, 2016, were as follows (in thousands):

2017			745
2018			125
Total future minimum lease payments			870

Manufacturing Agreements

On May 20, 2016, the Company signed a development and manufacturing services agreement with CMC ICOS Biologics, Inc. (“CMC”), pursuant to which CMC will conduct manufacturing development and, upon successful development of the manufacturing process, manufacture the Company’s next-generation Factor VIIa variant marzeptacog alfa (activated) that the Company intends to use in its clinical trials. The Company has agreed to a total of $3.8 million in payments to CMC pursuant to the initial statement of work under the Agreement, subject to completion of applicable work stages. As of December 31, 2016, the Company is obligated for $3.3 million in payments to CMC remaining under the agreement.

License Agreement Obligations

Under its technology license agreements to acquire certain technology rights, the Company has an obligation to pay minimum fees and then royalties based upon a percentage of any net sales of licensed products. License fees payable under the technology license agreements are $0.1 million in 2013 and each year thereafter until royalties commence. The technology license agreements also provide for future payments to be made by the Company upon the achievement of development milestones or cumulative sales milestones. Pursuant to the license and collaboration agreement with ISU Abxis (see Note 12 - Collaborations), the Company may be obligated to pay ISU Abxis up to $2.0 million in potential milestone payments. At December 31, 2016, no such milestones have been achieved. Under its agreement with Pfizer, which terminated as of June 2015 and was finalized as of December 2016, the Company may be obligated to make milestone and royalty payments to Pfizer up to $17.5 million payable upon the achievement of clinical, regulatory and commercial milestones. Following commercialization of any Product, Pfizer would also receive a single-digit royalty on net Product sales on a country-by-country basis for a predefined royalty term.

Convertible Notes

12 Months Ended

Dec. 31, 2016

Convertible Notes

9.	Redeemable Convertible Notes

On August 19, 2015, immediately prior to the Merger, the Company issued to Targacept stockholders non-interest bearing redeemable convertible notes (the “Notes”) in the aggregate principal amount of $37.0 million. The Notes do not bear interest. The principal amount of the Notes are convertible, at the option of each noteholder, into cash or into shares of the Company’s common stock at a conversion rate of $137.85 per share, and are payable in cash, if not previously redeemed or converted, at maturity on February 19, 2018, the 30-month anniversary of the closing of the issuance of the Notes.

In connection with the Pre-Closing Dividend, on August 19, 2015, Targacept entered into an indenture (the “Indenture”) with American Stock Transfer & Trust Company, LLC, as trustee, and an escrow agreement with American Stock Transfer & Trust Company, LLC and Delaware Trust Company, LLC, as escrow agent, under which $37.0 million, which represented the initial principal amount of the convertible notes, was deposited in a segregated escrow account for the benefit of the holders of the notes in order to facilitate the payment of the notes upon redemption or at maturity (the amount of such deposit together with interest accrued and capitalized thereon, the “Escrow Funds”). The Notes are the Company’s secured obligation, and the Indenture does not limit its other indebtedness, secured or unsecured.

Holders of the Notes may submit conversion notices, which are irrevocable, instructing the trustee to convert such Notes into shares of common stock at a conversion price of $137.85 per share. Following each conversion date, the Company will issue the number of whole shares of common stock issuable upon conversion as promptly as practicable (and in any event within 10 business days). The trustee will in turn release to the Company the respective amount of restricted cash to cover the stock issuance.

The conversion to common stock feature of the Notes was determined to be a derivative liability requiring bifurcation and separate accounting. The fair value of such conversion feature at issuance was determined to be $1.5 million. The bifurcation of the derivative liability from the estimated fair value of the Notes of $37.1 million at issuance resulted in a debt discount of $1.4 million. The Company elected to accrete the entire debt discount as interest expense immediately after the Merger. In addition, changes in the fair value of the derivative liability are being recorded within interest and other income in the consolidated statements of operations. The Company remeasures the derivative liability to fair value until the earlier of the conversion, redemption or maturity of the redeemable convertible notes.

For the year ended December 31, 2016 and 2015, the Company recognized interest expense of $0 and $1.4 million related to the amortization of the debt discount within interest expense on the Company’s consolidated statement of operations as the redeemable convertible notes are immediately fully redeemable at the option of the holders.

As of December 31, 2016, $17.3 million of the Notes were redeemed and $0.3 million of the Notes were converted into common stock. The Company recognized $0.1 million of gain on the extinguishment of Notes upon the redemption of the Notes during the year ended December 31, 2016.

Related Party Debt

Convertible Notes

8.	Convertible Notes – Related Parties

In May and June 2015, Catalyst Bio issued and sold convertible promissory notes in a series of closings in the aggregate principal amount of $1.9 million to existing stockholders, together with warrants to purchase shares of either the Catalyst Bio’s Series E preferred stock or the capital stock issued during the next financing. The convertible promissory notes accrued interest at a rate of 12% per annum and were to mature one year from the date of issuance.

As part of the debt financing, Catalyst Bio also issued and sold to each investor purchasing a convertible promissory note a warrant to purchase equity securities of the same type that the principal amount of the convertible promissory note issued to such investor converts into.

In conjunction with the second closing in June 2015 of the Series F convertible preferred stock financing, Catalyst Bio and the majority holders of the notes, amended the notes such that the closing constituted a qualified financing. Accordingly, the total outstanding principal amount of the notes of $1.9 million and all unpaid accrued interest of $0.03 million, were converted into 1,511,723 shares of Series F convertible preferred stock, and warrants for the purchase of 372,045 shares of Series F convertible preferred stock were issued to the note holders in connection with the conversion of the notes to Series F convertible preferred stock. All preferred stock and warrants were converted to common stock and warrants to purchase common stock upon the closing of the Merger.

For the years ended December 31, 2016 and 2015, the Company recognized interest expense of $0 and $1.5 million related to the accrued interest and amortization of the debt discount.

All outstanding shares of Catalyst Bio’s convertible preferred stock and warrants to purchase convertible preferred stock were converted into shares of the Company’s common stock and warrants to purchase common stock upon completion of the Merger.

Stock Based Compensation

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Compensation

10.	Stock Based Compensation

The Company assumed all of the outstanding options under Catalyst Bio’s 2004 Stock Plan (the “Catalyst Plan”) and all of the standalone options of Catalyst Bio that were not issued under the Catalyst Plan, in each case whether or not vested, outstanding immediately prior to the Merger, with such options henceforth representing the right to purchase that number of shares of the Company’s common stock equal to 0.0382 multiplied by the number of shares of Catalyst Bio common stock previously represented by such options. For accounting purposes, however, the Company is instead deemed to have assumed all of the options under the Targacept, Inc. 2000 Equity Incentive Plan and the 2006 Stock Incentive Plan and all of the standalone options of Targacept that were not issued under such plans outstanding immediately prior to the Merger (such plans and options, together with the Catalyst Plan and the standalone Catalyst options, the “Plans”), in addition to the Company’s 2015 Stock Incentive Plan (as subsequently amended and restated).

Total stock-based compensation recognized was as follows (in thousands):

	Year Ended December 31,
	2016		2015
Research and development	$	185	$	95
General and administrative		450		231
Total stock-based compensation	$	635	$	326

Valuation Assumptions

The Company estimated the fair value of stock options granted using the Black-Scholes option-pricing formula and a single option award approach. This fair value is being amortized ratably over the requisite service periods of the awards, which is generally the vesting period. The fair value of employee stock options was estimated using the following weighted-average assumptions for the years ended December 31, 2016 and 2015:

	Year Ended December 31,
	2016			2015
Expected term	6.14 years			5.56 years
Expected volatility		76.59	%		68.64	%
Risk-free interest rate		1.53	%		1.34	%
Expected dividend yield		0	%		0	%

Expected Term. Under the Company’s stock option plans, the expected term of options granted is determined using the simplified method which calculates expected term as the midpoint between the vesting date and the expiration date for each award.

Expected Volatility. Since the Company was a private entity prior to the merger in August 2015 with no historical data regarding the volatility of its common stock, the expected volatility used is based on the volatility of similar publicly traded entities, referred to as “guideline” companies.

Risk-Free Interest Rate. The risk-free rate is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term of the options.

Expected Dividend Yield. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, assumed an expected dividend yield of zero.

The following table summarizes stock option activity under the plans and related information:

	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (thousands)
Outstanding — December 31, 2014		16,683		$	134.40		5.51
Options assumed in merger(1)		94,721		$	227.40		4.01
Options granted		45,039		$	44.70		9.81
Options exercised		(254	)	$	50.70
Options forfeited		(2,436	)	$	127.20
Options canceled		(7,119	)	$	708.00
Outstanding — December 31, 2015		146,634		$	147.45		5.51		15,524.91
Options granted		14,706		$	23.70				—
Fractional shares written off in connection with the merger⁽¹⁾		(4	)	$	—
Options canceled		(13,773	)		259.05
Options forfeited		(6,573	)	$	64.95
Outstanding — December 31, 2016		140,990		$	128.25		3.93		—
Exercisable — December 31, 2016		106,472		$	152.70		2.28		—
Vested and expected to vest — December 31, 2016		68,977		$	74.70		7.09		—
Shares Available to be granted — December 31, 2016		85,849

(1)

In connection with the merger, the Company assumed stock options covering an aggregate of 94,721 shares of common stock. The company also assumed 190 shares of Restricted Stock Awards which vested in two equal annual installments beginning on December 31, 2015 and fully vesting on December 31, 2016 and excludes 4 aggregate fractional shares written off as a result of the conversion ratio applied to options assumed in the merger. Total stock based compensation related to these restricted stock awards was $0.02 million for year ended December 31, 2016.

As of December 31, 2016, 85,849 shares of common stock were available for future grant, 140,990 options to purchase shares of common stock were outstanding under the 2015 Stock Plan, as amended, and the Company had unrecognized employee stock-based compensation expense of $1.0 million, related to unvested stock awards, which is expected to be recognized over an estimated weighted-average period of 2.57 years.

Options Granted to Nonemployees

During the years ended December 31, 2016 and 2015, options to purchase 800 and 1,317 shares, respectively, of common stock were issued to consultants that vest over one to four years with a weighted-average exercise price of $20.40 and $97.80 per share, respectively. During the years ended December 31, 2016, and 2015, the Company recorded stock-based compensation expense attributable to these nonemployee stock awards of $0.05 million and $0.04 million, respectively.

The estimated grant-date fair values of the nonemployee stock options were determined using the Black-Scholes valuation model and the following assumptions:

	Year Ended December 31,
	2016			2015
Non-Employee Stock Options:
Risk-free interest rate		2.39	%		1.30	%
Expected term (in years)		9.74			5.64
Dividend yield		—			—
Volatility		101.12	%		69.98	%

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

11.	Income Taxes

The Company has incurred cumulative operating losses since inception and, consequently, has not recorded any income tax expense for the years ended December 31, 2016 and 2015 due to its net operating loss position.

The reconciliation of the federal statutory income tax rate to the Company’s effective tax rate for the years ended December 31, 2016 and 2015 are as follows:

	Year Ended December 31,
	2016			2015
Tax at statutory federal rate		34.00	%		34.00	%
State Tax (benefit)—net of federal benefit		1.12	%		1.33	%
Permanent differences		7.95	%		-8.00	%
R&D Credits		3.16	%		11.59	%
Derecognition due to Sec. 382 and 383 Limitations		0.00	%		-240.87	%
Change in Valuation Allowance		-46.66	%		204.17	%
Other		0.43	%		-2.22	%
Effective tax rate		—			—

Significant components of the Company’s deferred tax assets as of December 31, 2016 and 2015 consist of the following (in thousands):

	Year Ended December 31,
	2016			2015
Deferred tax assets:
Accruals and reserves	$	1,137		$	1,285
Net Operating Loss Carry forwards		25,944			17,650
R&D Tax Credit Carry forwards		3,174			2,625
Fixed and intangible assets		114			95
Valuation Allowance		(30,369	)		(21,655	)
Net deferred tax assets:		—			—

Based on the available objective evidence at December 31, 2016, the Company does not believe it is more likely than not that the net deferred tax assets will be realizable. Accordingly, the Company has provided a full valuation allowance against its net deferred tax assets at December 31, 2016 and 2015.

As of December 31, 2016, after consideration of certain limitations (see below), the Company had approximately $68.3 million federal and $46.6 million state net operating loss carry forwards (“NOL”) available to reduce future taxable income which, if unused, will begin to expire in 2025 for federal and 2017 for state tax purposes.

As of December 31, 2016, the Company also had tax credit carry forwards available to offset future tax liabilities of approximately $0.5 million for federal and $5.6 million for state. The federal tax credit will begin to expire in 2024 and the state tax credit does not expire.

If the Company experiences a greater than 50 percentage point aggregate change in ownership over a three-year period (a Section 382 ownership change), utilization of its pre-change NOL carry forwards are subject to annual limitation under Section 382 of the Internal Revenue Code (California has similar provisions). The annual limitation is determined by multiplying the value of the Company’s stock at the time of such ownership change by the applicable long-term tax-exempt rate. Such limitations may result in expiration of a portion of the NOL carry forwards before utilization. The Company has determined that ownership changes occurred on December 31, 2007 and August 20, 2015. Approximately $76.3 million and $56.1 million of the NOLs will expire unutilized for federal and California purposes, respectively. The Company has derecognized NOL related deferred tax assets in the tax affected amounts of $25.9 million and $3.3 million for federal and California purposes, respectively.

All of the federal R&D credits could expire unutilized as well, whereas none of the California R&D credits are subject to expiration. Approximately $5.6 million of gross federal R&D credit-related deferred tax assets were derecognized due to the Section 383 limitation. The ability of the Company to use its remaining NOL carry forwards may be further limited if the Company experiences a Section 382 ownership change as a result of future changes in its stock ownership.

Accounting for Uncertainty in Income Taxes

The Company only recognizes tax benefits if it is more likely than not that they will be sustained upon audit by the relevant tax authority based upon their technical merits. An uncertain tax position will not be recognized if it has less than a 50% likelihood of being sustained.

The Company had approximately $1.5 million and $1.3 million of unrecognized tax benefits as of both December 31, 2016 and 2015. As the Company has a full valuation allowance on its deferred tax assets, the unrecognized tax benefits have reduced the deferred tax assets and the valuation allowance in the same amount. The Company does not expect the amount of unrecognized tax benefits to materially change in the next twelve months. A reconciliation of the beginning and ending balance of the unrecognized tax benefits is as follows (in thousands):

Beginning Balance at January 1, 2015	$	2,570
Increase/(Decrease) of unrecognized tax benefits taken in prior years		(1,347	)
Increase/(Decrease) of unrecognized tax benefits related to current year		91
Ending Balance at December 31, 2015	$	1,314

Beginning Balance at January 1, 2016	$	1,314
Increase/(Decrease) of unrecognized tax benefits taken in prior years		6
Increase/(Decrease) of unrecognized tax benefits related to current year		219
Ending Balance at December 31, 2016	$	1,539

Interest and penalty related to unrecognized tax benefits would be included as income tax expense in the Company’s consolidated statements of operations. As of December 31, 2016 and 2015, the Company had not recognized any tax-related penalties or interest in its consolidated financial statements.

The Company files income tax returns in the United States and California. The Company is not currently under examination by income tax authorities in federal, state or other jurisdictions. As of December 31, 2016 and 2015, the Company had no uncertain tax positions which affected its financial position and its results of operations or its cash flow, and will continue to evaluate for uncertain positions in the future. The Company is subject to United States federal and state income tax examinations by authorities for all tax years due to accumulated net operating losses that are being carried forward for tax purposes.

Collaborations

12 Months Ended

Dec. 31, 2016

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Collaborations

12.	Collaborations

Pfizer

On August 20, 2013 the Company and Pfizer signed an amendment to the Factor VIIa collaboration agreement in which the companies agreed to provide specific mutual releases and covenants and modify certain milestone payment schedules in the agreement. Per the amendment, Pfizer agreed to make two non-refundable $1.5 million annual license maintenance payments to the Company, payable on August 1, 2014 and 2013. The annual license maintenance payments received were being amortized to contract revenue over the estimated expected performance period under the arrangement, which the Company estimated was to end August 1, 2015.

On April 2, 2015, Pfizer notified the Company that it was exercising its right to terminate the research and license agreement effective June 1, 2015. The termination became effective 60 days after the Company’s receipt of the termination notice. On June 1, 2015, the license and certain rights under the research and license agreement terminated and reverted to the Company. The Company plans to continue clinical development of this product candidate. The Company revised the expected period of performance to end on June 1, 2015, which was the effective termination of all performance obligations of the Company under the research and license agreement. Accordingly, all deferred revenue was recognized through June 1, 2015.

Contract revenue related to the agreement with Pfizer was $0 and $1.3 million during the years ended December 31, 2016 and 2015, respectively. The deferred revenue balance related to the Pfizer collaboration was zero as of both December 31, 2016 and 2015.

On December 8, 2016, the Company signed an agreement with Pfizer pursuant to which the parties terminated the research and license agreement that was signed on June 29, 2009. Pursuant to the new agreement, Pfizer granted the Company an exclusive license to Pfizer’s proprietary rights for manufacturing and processes that apply to Factor VIIa variants, CB 813a (marzeptacog alfa (activated)). Pfizer has also transferred and will transfer to the Company documentation related to the development, manufacturing and testing of the Products, including the Investigational New Drug (“IND”) application as well as the orphan drug designation.

As part of the new agreement, the Company agreed to make contingent cash payments to Pfizer in an aggregate amount equal to up to $17.5 million, payable upon the achievement of clinical, regulatory and commercial milestones. Following commercialization of any covered product, Pfizer would also receive a single-digit royalty on net product sales on a country-by-country basis for a predefined royalty term.

ISU Abxis

On June 16, 2013, the Company signed a license and collaboration agreement with ISU Abxis, whereby the Company licensed its proprietary human Factor IX products to ISU Abxis for initial development in South Korea. Under the terms of the agreement, ISU Abxis is responsible for development and manufacturing of the licensed products through Phase 1/2 clinical trials. Until the completion of Phase 1/2 development, ISU Abxis also has a right of first refusal with respect to commercialization rights for the licensed products in South Korea. The Company has the sole rights and responsibility for worldwide development, manufacture and commercialization of Factor IX products after Phase 1/2 development, unless ISU Abxis has exercised its right of first refusal regarding commercialization rights in South Korea, in which case the Company’s rights are in the entire world excluding South Korea. ISU’s rights will also terminate if the Company enters into a license agreement with another party to develop, manufacture and commercialize Factor IX products in at least two major market territories.

ISU Abxis paid the Company an up-front signing fee of $1.75 million and is obligated to pay to the Company contingent milestone-based payments on the occurrence of certain defined development events, and reimbursement for a portion of the Company’s costs relating to intellectual property filings and maintenance thereof on products. The Company is obligated to pay ISU Abxis a percentage of all net profits it receives from collaboration products.

Contract revenue of $0.4 million and $0.4 million for the years ended December 31, 2016 and 2015, respectively, reflected the amortization of the up-front fee over the estimated period of the Company’s performance obligations under the agreement, which was assessed to be four years beginning in September 2013 when the agreement was executed. The deferred revenue balance related to the ISU Abxis collaboration was $0.3 million and $0.7 million as of December 31, 2016 and 2015, respectively.

Interest and Other Income

12 Months Ended

Dec. 31, 2016

Other Income And Expenses [Abstract]

Interest and Other Income

13.	Interest and Other Income

The following table shows the detail of other income, net for the years ended December 31, 2016 and 2015 (in thousands):

	Year Ended December 31,
	2016		2015
Gain on sale of NNR assets	$	1,674	$	—
Change in derivative liability		1,156		387
Gain on sale of fixed assets		557		—
Other Income, net		86		131
Total Other Income, net	$	3,473	$	518

Common Stock

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Common Stock

14.	Common Stock

On March 16, 2016, the Company signed a Capital on Demand^TM Sales Agreement with JonesTrading Institutional Services LLC (“JonesTrading”). In accordance with the terms of the sales agreement, the Company may offer and sell shares of its common stock having an aggregate offering price up to $6.5 million, subject to certain limitations, from time to time in one or more public offerings of the Company’s common stock, with JonesTrading acting as agent, in transactions pursuant to a shelf registration statement that was declared effective by the SEC on April 28, 2016.

For the year ended December 31, 2016, the Company sold 39,743 shares of common stock in the open market at a weighted-average selling price of $25.08 per share, for net proceeds (net of commissions) of $1.0 million in the Capital on Demand^TM program.

For the year ended December 31, 2016, the Company expensed approximately $0.1 million of costs for the offering, excluding JonesTrading commissions. The Company charged $0.03 million of these costs against additional paid-in capital for the year ended December 31, 2016.

As of February 28, 2017, the Company had up to $3.6 million of common stock available for sale under the Controlled Equity Offering^TM program.

Net Loss per Common Share

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Net Loss per Common Share

15.	Net Loss per Common Share

The following table sets forth the computation of the basic and diluted net loss per common share during the years ended December 31, 2016 and 2015 (in thousands, except share and per share data):

	Year Ended December 31,
	2016			2015
Net loss, basic and diluted	$	(16,945	)	$	(14,762	)
Weighted-average number of shares used in computing net loss per share, basic and diluted		779,166			295,272
Net loss per share, basic and diluted	$	(21.75	)	$	(49.99	)

Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities on an as-if converted basis that were not included in the diluted per share calculations because they would be anti-dilutive were as follows:

	Year Ended December 31,
	2016		2015
Options to purchase common stock		140,990		146,726
Common stock warrants		12,063		12,063
Redeemable convertible notes		140,743		244,783
Total		293,796		403,572

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of the Company and its subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation. The Company’s consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”).
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, convertible notes and related warrants up to the date of conversion, common stock and stock-based compensation. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company invests its excess cash in bank deposits, consisting primarily of money market mutual funds. The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents.
Restricted Cash	Restricted Cash Restricted cash consists of certain checking, money market and certificate of deposit accounts that are: (i) pledged to or held in a segregated escrow account by the Company’s correspondent banks for the benefit of the holders of the redeemable convertible notes in order to facilitate the payment of the redeemable convertible notes upon redemption or at maturity as discussed in Note 3 - Fair Value Measurements or (ii) pledged as collateral for the Company’s corporate credit card and deposit for its facility lease.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires that an entity maximize the use of observable inputs when estimating fair value. The fair value hierarchy includes the following three-level classification which is based on the market observability of the inputs used for estimating the fair value of the assets or liabilities being measured: Level 1 – Quoted prices in active markets for identical assets or liabilities. Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability. Fair value accounting is applied for all financial assets and liabilities and non-financial assets and liabilities that are recognized at fair value in the financial statements on a recurring basis (at least annually).
Property and Equipment	Property and Equipment Property and equipment are stated at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets, which are three years for computer equipment and software, and three to seven years for laboratory and office equipment, furniture and leasehold improvements.
Investments	Investments All investments have been classified as “available-for-sale” and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and reevaluates such designation as of each balance sheet date. Unrealized gains and losses are excluded from earnings and are reported as a component of comprehensive loss. Realized gains and losses and declines in fair value determined to be other-than-temporary, if any, on available-for-sale securities are included in interest and other income. The cost of securities sold is based on the specific-identification method. Interest on short-term investments is included in interest and other income.
Derivative Liability	Derivative Liability The embedded redemption feature in the redeemable convertible notes, which are convertible into shares of the Company’s common stock, is accounted for as a derivative liability at its estimated fair value. The derivative is subject to remeasurement at the end of each reporting period, with changes in fair value recognized as a component of interest and other income, in the consolidated statements of operations. The Company will continue to adjust the liability for changes in fair value until the earlier of the conversion, redemption or maturity of the redeemable convertible notes, as of December 31, 2016 the fair value was immaterial.
Revenue Recognition	Revenue Recognition The Company enters into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments, full time equivalent based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations. Revenue is recognized when the four basic criteria for revenue recognition are met: (1) persuasive evidence of an arrangement exists; (2) transfer of technology has been completed or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured. Revenue recognition for multiple element revenue arrangements will have deliverables associated with the arrangement divided into separate units of accounting provided that (i) a delivered item has value to the customer on a standalone basis and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the control of the vendor. As a biotechnology company with unique and specialized technological undelivered performance obligations associated with its collaborations, the Company’s multiple element arrangements most often involve deliverables and consideration that do not meet the criteria for having stand-alone value. Deliverables and performance obligations are accounted for under a single unit of accounting when they do not have stand-alone value and the related consideration is recognized as revenue over the estimated period of when the performance obligations are to be performed. The revenue is recognized on a proportional performance basis when the levels of the performance obligations under an arrangement can be reasonably estimated and on a straight-line basis when they cannot. The Company’s collaboration agreements entitle it to additional payments upon the achievement of performance-based milestones related to product development, regulatory actions and commercial events in certain geographic areas. Milestones that are not deemed probable or that are tied to counter-party performance are not included in the Company’s revenue until the performance conditions are met. If a collaborative agreement milestone is deemed to be substantive, as defined in the accounting rules, the Company is permitted to recognize revenue related to the milestone payment in its entirety. In the event milestones are deemed non-substantive, the Company recognizes, and defers if applicable, payments for the achievement of such non-substantive milestones over the estimated period of performance applicable to each collaborative agreement using the proportional performance method or on a straight-line basis, as appropriate. Amounts received under a collaborative agreement prior to satisfying revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Deferred revenue is recorded on the Company’s consolidated balance sheet as short-term or long-term based on its best estimate as to when such revenue will be recognized. Short-term deferred revenue consists of amounts that the Company expects to recognize as revenue in the next 12 months. Amounts that the Company expects will not be recognized prior to the next 12 months are classified as long-term deferred revenue. The Company’s performance obligations under its collaboration arrangements also consist of participation on steering committees and the performance of other research and development and business development services. The timing for satisfying these performance obligations can be difficult to estimate and can be subject to change over the course of these agreements. A change in the estimated timing for satisfying the Company’s performance obligations could change the timing and amount of revenue that the Company recognizes and records in future periods.
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. Research and development costs consist of payroll and other personnel-related expenses, laboratory supplies and reagents, contract research and development services, and consulting costs, as well as allocations of facilities and other overhead costs. Under the Company’s collaboration agreements, certain specific expenditures are reimbursed by third parties. During the years ended December 31, 2016 and 2015, the Company recorded a reduction to research and development expenses of $0.1 million and $0.9 million, respectively related to these reimbursements.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents, investments and accounts receivable. The Company’s investment policy restricts cash investments to high credit quality, investment grade investments. The Company believes that it has established guidelines for investment of its excess cash that maintain safety and liquidity through its policies on diversification and investment maturity. The Company is exposed to credit risk in the event of default by the institutions holding the cash and cash equivalents to the extent of the amounts recorded on the balance sheets The Company’s accounts receivable at December 31, 2016 was $0.01 million, due from ISU Abxis. The Company has incurred no credit losses to date. The Company does not require collateral from its collaboration partners.
Income Taxes	Income Taxes Income taxes are computed using the liability method. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company follows the authoritative guidance on accounting for uncertainty in income taxes. This guidance prescribes a more-likely-than-not threshold for financial statement recognition and measurement of a tax position taken in the Company’s income tax returns. This interpretation also provides guidance on accounting for interest and penalties and associated with tax positions, accounting for income taxes in interim periods and income tax disclosures. The Company’s policy is to include penalties and interest expense related to income taxes as a component of other expense and interest expense, respectively, as necessary.
Stock-Based Compensation	Stock-Based Compensation The Company measures the cost of employee and director services received in exchange for an award of equity instruments based on the fair value of the award on the date of grant and recognizes the related expense over the period during which the employee or director is required to provide service in exchange for the award on a straight-line basis. The Company uses the Black-Scholes option-pricing valuation model to estimate the grant-date fair value of stock-based awards. The determination of fair value for stock-based awards on the date of grant using an option-pricing model requires management to make certain assumptions regarding a number of variables. The Company records stock-based compensation as compensation expense, net of the estimated impact of forfeited awards. The Company applies a forfeiture rate to stock-based compensation expense using historical data to estimate pre-vesting option forfeitures. The Company estimates forfeitures at the time of grant, and revises those estimates in subsequent periods if actual forfeitures differ materially from those original estimates. As such, the Company recognizes stock-based compensation expense only for those stock-based awards that are expected to vest, over their requisite service period, based on the vesting provisions of the individual grants. For nonemployee stock-based awards, the measurement date on which the fair value of the stock-based award is calculated is equal to the earlier of (i) the date at which a commitment for performance by the counterparty to earn the equity instrument is reached or (ii) the date at which the counterparty’s performance is complete. The Company recognizes stock-based compensation expense for the fair value-based measurement of the nonemployee awards using the Black Scholes option-pricing valuation model and the awards are typically subject to periodic re-measurement over the period that services are rendered.
Deferred Rent	Deferred Rent The Company’s facilities lease agreement provides for an escalation of rent payments each year. The Company records rent expense on a straight-line basis over the term of the lease. The difference between the amount of expense recognized and the amount of rent paid is recorded as deferred rent in the accompanying consolidated balance sheets.
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is the same as basic net loss per share, since the effects of potentially dilutive securities are antidilutive given the net loss of the Company for all periods presented.

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables present the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 and 2015 (in thousands):

	December 31, 2016
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	10,156		—		—	$	10,156
Restricted cash (money market funds)⁽²⁾		19,593		—		—		19,593
U.S. government agency securities⁽³⁾		6,800		—		—		6,800
Total financial assets	$	36,549	$	—	$	—	$	36,549
Financial liabilities:
Derivative liability⁽⁴⁾		—		—		—	$	—
Total financial liabilities	$	—	$	—	$	—	$	—

(1)	Included in Cash and Cash Equivalents on accompanying consolidated balance sheets.

(2)	$19.4 million of restricted cash serves as full collateral for the redeemable convertible notes and $125,000 of restricted cash serves as collateral for the Company’s corporate credit card and deposit for its facility lease.

(3)	Included in Short Term Investments on accompanying consolidated balance sheets.

	December 31, 2015
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	28,927	$	—	$	—	$	28,927
Restricted cash (money market funds)⁽²⁾		33,919		—		—		33,919
Municipal bonds⁽³⁾		—		296		—		296
Corporate notes⁽³⁾		—		3,106		—		3,106
Total financial assets	$	62,846	$	3,402	$	—	$	66,248
Financial liabilities:
Derivative liability⁽⁴⁾	$	—	$	—	$	1,156	$	1,156
Total financial liabilities	$	—	$	—	$	1,156	$	1,156

(1)	Included in Cash and Cash Equivalents on accompanying consolidated balance sheets.

(2)	$33.8 million of restricted cash serves as full collateral for the redeemable convertible notes and $125,000 of restricted cash serves as collateral for the Company’s corporate credit card and deposit for its facility lease.

(3)	Included in Short Term Investments on accompanying consolidated balance sheets.

(4)

Fair Values of Derivative Liabilities Estimated Using Black-Scholes Valuation Model

	As of December 31,
	2016			2015
Expected term	1.01			2.00
Expected volatility		80.6	%		81.7	%
Risk-free interest rate		1.20	%		1.06	%
Expected dividend yield		0	%		0	%

Derivative

Derivative Liability Measured at Estimated Fair Value Using Unobservable Inputs

The following table presents the activity for the derivative liability measured at estimated fair value using unobservable inputs for the year ended December 31, 2016 (in thousands):

	Derivative Liability
Balance as of December 31, 2015	$	1,156
Change in fair value included in interest and other income		(1,057	)
Gain on extinguishment of redeemable convertible notes		(99	)
Balance as of December 31, 2016	$	—

Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2016

Investments All Other Investments [Abstract]

Cash Equivalents, Restricted Cash and Short-term and Long-term Investments Classified as Available-for-sale Securities

Cash equivalents, restricted cash and short-term and long-term investments, all of which are classified as available-for-sale securities, consisted of the following (in thousands):

December 31, 2016	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Money market funds	$	10,156	$	—	$	—		$	10,156
Restricted cash (money market funds)		19,593		—		—			19,593
U.S. government agency securities		6,802		—		(2	)		6,800
Total financial assets	$	36,551	$	—	$	(2	)	$	36,549
Classified as:
Cash and cash equivalents								$	10,156
Restricted cash (money market funds)									19,593
Short-term investments									6,800
								$	36,549

December 31, 2015	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Money market funds	$	28,927	$	—	$	—		$	28,927
Restricted cash (money market funds)		33,919		—		—			33,919
Municipal bonds		295		1		—			296
Corporate notes		3,106		1		(1	)		3,106
Total financial assets	$	66,247	$	2	$	(1	)	$	66,248
Classified as:
Cash and cash equivalents								$	28,927
Restricted cash (money market funds)									33,919
Short-term investments									3,402
								$	66,248

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Property Plant And Equipment [Abstract]

Schedule of Property and equipment

Property and equipment consisted of the following (in thousands):

	Year Ended December 31,
	2016			2015
Laboratory and office equipment	$	—		$	4,458
Furniture		317			321
Leasehold improvements		1,613			1,591
Computer equipment		230			21
Software		144			8
		2,304			6,399
Less accumulated depreciation and amortization		(1,860	)		(5,701	)
Property and equipment, net	$	444		$	698

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments And Contingencies Disclosure [Abstract]

Expected Future Lease Payments Under All Operating Leases

Future minimum lease payments under all non-cancelable operating leases at December 31, 2016, were as follows (in thousands):

2017			745
2018			125
Total future minimum lease payments			870

Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Summary of Stock-Based Compensation Recognized

Total stock-based compensation recognized was as follows (in thousands):

	Year Ended December 31,
	2016		2015
Research and development	$	185	$	95
General and administrative		450		231
Total stock-based compensation	$	635	$	326

Summary of Option Activity

The following table summarizes stock option activity under the plans and related information:

	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (thousands)
Outstanding — December 31, 2014		16,683		$	134.40		5.51
Options assumed in merger(1)		94,721		$	227.40		4.01
Options granted		45,039		$	44.70		9.81
Options exercised		(254	)	$	50.70
Options forfeited		(2,436	)	$	127.20
Options canceled		(7,119	)	$	708.00
Outstanding — December 31, 2015		146,634		$	147.45		5.51		15,524.91
Options granted		14,706		$	23.70				—
Fractional shares written off in connection with the merger⁽¹⁾		(4	)	$	—
Options canceled		(13,773	)		259.05
Options forfeited		(6,573	)	$	64.95
Outstanding — December 31, 2016		140,990		$	128.25		3.93		—
Exercisable — December 31, 2016		106,472		$	152.70		2.28		—
Vested and expected to vest — December 31, 2016		68,977		$	74.70		7.09		—
Shares Available to be granted — December 31, 2016		85,849

(1)

Employee Stock Option

Summary of Weighted Average Valuation Assumptions Used to Estimate Fair Value

The fair value of employee stock options was estimated using the following weighted-average assumptions for the years ended December 31, 2016 and 2015:

	Year Ended December 31,
	2016			2015
Expected term	6.14 years			5.56 years
Expected volatility		76.59	%		68.64	%
Risk-free interest rate		1.53	%		1.34	%
Expected dividend yield		0	%		0	%

Non Employee Stock Option

Summary of Weighted Average Valuation Assumptions Used to Estimate Fair Value

The estimated grant-date fair values of the nonemployee stock options were determined using the Black-Scholes valuation model and the following assumptions:

	Year Ended December 31,
	2016			2015
Non-Employee Stock Options:
Risk-free interest rate		2.39	%		1.30	%
Expected term (in years)		9.74			5.64
Dividend yield		—			—
Volatility		101.12	%		69.98	%

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Reconciliation of Federal Income Tax Rate to Company's Effective Tax Rate

The reconciliation of the federal statutory income tax rate to the Company’s effective tax rate for the years ended December 31, 2016 and 2015 are as follows:

	Year Ended December 31,
	2016			2015
Tax at statutory federal rate		34.00	%		34.00	%
State Tax (benefit)—net of federal benefit		1.12	%		1.33	%
Permanent differences		7.95	%		-8.00	%
R&D Credits		3.16	%		11.59	%
Derecognition due to Sec. 382 and 383 Limitations		0.00	%		-240.87	%
Change in Valuation Allowance		-46.66	%		204.17	%
Other		0.43	%		-2.22	%
Effective tax rate		—			—

Components of the Company's Deferred Tax Assets (Liabilities)

Significant components of the Company’s deferred tax assets as of December 31, 2016 and 2015 consist of the following (in thousands):

	Year Ended December 31,
	2016			2015
Deferred tax assets:
Accruals and reserves	$	1,137		$	1,285
Net Operating Loss Carry forwards		25,944			17,650
R&D Tax Credit Carry forwards		3,174			2,625
Fixed and intangible assets		114			95
Valuation Allowance		(30,369	)		(21,655	)
Net deferred tax assets:		—			—

Unrecognized Tax Benefits

A reconciliation of the beginning and ending balance of the unrecognized tax benefits is as follows (in thousands):

Beginning Balance at January 1, 2015	$	2,570
Increase/(Decrease) of unrecognized tax benefits taken in prior years		(1,347	)
Increase/(Decrease) of unrecognized tax benefits related to current year		91
Ending Balance at December 31, 2015	$	1,314

Beginning Balance at January 1, 2016	$	1,314
Increase/(Decrease) of unrecognized tax benefits taken in prior years		6
Increase/(Decrease) of unrecognized tax benefits related to current year		219
Ending Balance at December 31, 2016	$	1,539

Interest and Other Income (Tables)

12 Months Ended

Dec. 31, 2016

Other Income And Expenses [Abstract]

Detail of Other Income, Net

The following table shows the detail of other income, net for the years ended December 31, 2016 and 2015 (in thousands):

	Year Ended December 31,
	2016		2015
Gain on sale of NNR assets	$	1,674	$	—
Change in derivative liability		1,156		387
Gain on sale of fixed assets		557		—
Other Income, net		86		131
Total Other Income, net	$	3,473	$	518

Net Loss per Common Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Basic and Diluted Net Loss Per Common Share

The following table sets forth the computation of the basic and diluted net loss per common share during the years ended December 31, 2016 and 2015 (in thousands, except share and per share data):

	Year Ended December 31,
	2016			2015
Net loss, basic and diluted	$	(16,945	)	$	(14,762	)
Weighted-average number of shares used in computing net loss per share, basic and diluted		779,166			295,272
Net loss per share, basic and diluted	$	(21.75	)	$	(49.99	)

Anti-dilutive Security not Included In Diluted per Share Calculations

	Year Ended December 31,
	2016		2015
Options to purchase common stock		140,990		146,726
Common stock warrants		12,063		12,063
Redeemable convertible notes		140,743		244,783
Total		293,796		403,572

Nature of Operations - Additional Information (Detail) $ in Thousands			12 Months Ended
	Feb. 10, 2017 shares	Aug. 20, 2015	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Organization and Nature of Operations [Line Items]
Common stock, shares outstanding \| shares			801,756	762,005
Accumulated deficit			$ 147,982	$ 131,037
Cash, cash equivalents and short-term investments			17,100
Net loss			16,945	14,762
Cash used in operations			$ 18,472	$ 19,118
Targacept
Organization and Nature of Operations [Line Items]
Reverse stock split ratio		0.142857
2017 Reverse Stock Split
Organization and Nature of Operations [Line Items]
Reverse stock split, description			On February 10, 2017, the Company effected a reverse stock split of its common stock at a ratio of 1-for-15 (“2017 Reverse Stock Split”). The 2017 Reverse Stock Split was approved by the Company’s stockholders at a special meeting of stockholders held on February 2, 2017. As a result of the 2017 Reverse Stock Split, each 15 pre-split shares of common stock outstanding were automatically combined into one new share of common stock, and the number of outstanding shares of common stock on the date of the split was reduced from approximately 13.0 million shares to approximately 868,000 shares.
Common stock, shares outstanding \| shares			13,000,000
Subsequent Event \| 2017 Reverse Stock Split
Organization and Nature of Operations [Line Items]
Reverse stock split ratio	0.06667
Common stock, shares outstanding \| shares	868,000

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Reduction to research and development expenses	$ 100	$ 900
Accounts receivable	31	$ 492
ISU Abxis
Significant Accounting Policies [Line Items]
Accounts receivable	$ 10
Computer equipment
Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Laboratory and office equipment \| Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Laboratory and office equipment \| Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Furniture \| Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Furniture \| Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Leasehold improvements \| Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Leasehold improvements \| Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives	7 years

Assets and Liabilities Measured at Fair Value (Detail) - USD ($)
$ in Thousands

Dec. 31, 2016

Dec. 31, 2015

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

$ 36,549

$ 66,248

Liabilities, fair value

1,156

U.S. Government Agency Securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

6,800

Municipal Bonds

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

296

Corporate Notes

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

3,106

Money Market Funds

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[2]

10,156

28,927

Restricted cash (money market funds)

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

19,593

^[3]

33,919

^[4]

Fair Value, Inputs, Level 1

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

36,549

62,846

Fair Value, Inputs, Level 1 | U.S. Government Agency Securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

6,800

Fair Value, Inputs, Level 1 | Money Market Funds

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[2]

10,156

28,927

Fair Value, Inputs, Level 1 | Restricted cash (money market funds)

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

$ 19,593

^[3]

33,919

^[4]

Fair Value, Inputs, Level 2

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

3,402

Fair Value, Inputs, Level 2 | Municipal Bonds

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

296

Fair Value, Inputs, Level 2 | Corporate Notes

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

3,106

Fair Value, Inputs, Level 3

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Liabilities, fair value

1,156

Derivative liability

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Liabilities, fair value

^[5]

1,156

Derivative liability | Fair Value, Inputs, Level 3

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Liabilities, fair value

^[5]

$ 1,156

[1]	Included in Short Term Investments on accompanying consolidated balance sheets.
[2]	Included in Cash and Cash Equivalents on accompanying consolidated balance sheets.
[3]	$19.4 million of restricted cash serves as full collateral for the redeemable convertible notes and $125,000 of restricted cash serves as collateral for the Company’s corporate credit card and deposit for its facility lease.
[4]	$33.8 million of restricted cash serves as full collateral for the redeemable convertible notes and $125,000 of restricted cash serves as collateral for the Company’s corporate credit card and deposit for its facility lease.
[5]	The fair value of the derivative liability is measured using the Black-Scholes option-pricing valuation model. Inputs used to determine the estimated fair value of the conversion option include the fair value of the underlying common stock at the valuation measurement date, the remaining contractual term of the conversion option, risk-free interest rates, expected dividends and expected volatility of the price of the underlying common stock. In addition, the Company estimated the convertible redeemable note exchange rate based on an analysis of its actual exchange of notes for cash redemption or exchange of notes for conversion to common stock. See Note 9 - Redeemable Convertible Notes for further detail.

Assets and Liabilities Measured at Fair Value (Parenthetical) (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash	$ 19,468,000	$ 33,794,000
Collateral for Redeemable Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash	19,400,000	33,800,000
Collateral for Corporate Credit Card and Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash	$ 125,000	$ 125,000

Derivative Liability Measured at Estimated Fair Value Using Unobservable Inputs (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Fair Value Disclosures [Abstract]
Balance as of December 31, 2015	$ 1,156
Change in fair value included in interest and other income	(1,057)
Gain on extinguishment of redeemable convertible notes	$ (99)

Fair Values of Derivative Liabilities Estimated Using Black-Scholes Valuation Model (Detail) - Derivative liability	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected term	1 year 4 days	2 years
Expected volatility	80.60%	81.70%
Risk-free interest rate	1.20%	1.06%
Expected dividend yield	0.00%	0.00%

Cash Equivalents, Restricted Cash and Short-term and Long-term Investments Classified as Available-for-sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 36,551	$ 66,247
Gross Unrealized Gains		2
Gross Unrealized Losses	(2)	(1)
Estimated Fair Value	36,549	66,248
Money Market Funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,156	28,927
Estimated Fair Value	10,156	28,927
Money Market Funds \| Restricted cash (money market funds)
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	19,593	33,919
Estimated Fair Value	19,593	33,919
U.S. Government Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,802
Gross Unrealized Losses	(2)
Estimated Fair Value	6,800
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		295
Gross Unrealized Gains		1
Estimated Fair Value		296
Corporate Notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		3,106
Gross Unrealized Gains		1
Gross Unrealized Losses		(1)
Estimated Fair Value		3,106
Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	10,156	28,927
Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 6,800	$ 3,402

Financial Instruments - Additional Information (Detail)	12 Months Ended
Financial Instruments - Additional Information (Detail)	Dec. 31, 2016 USD ($)
Financial Instrument [Line Items]
Significant realized gains or losses on available-for-sale securities	$ 0
Maximum
Financial Instrument [Line Items]
Available for sale securities contractual maturities	1 year

Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,304	$ 6,399
Less accumulated depreciation and amortization	(1,860)	(5,701)
Property and equipment, net	444	698
Software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	144	8
Laboratory and office equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		4,458
Furniture
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	317	321
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,613	1,591
Computer equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 230	$ 21

Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Depreciation expense	$ 400,000	$ 500,000
Gain on sale of equipment	$ 600,000	$ 0

Restructuring Actions - Additional Information (Detail)	1 Months Ended	12 Months Ended
Restructuring Actions - Additional Information (Detail)	Sep. 30, 2016 Employee	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Restructuring Cost And Reserve [Line Items]
Proceeds from sale of equipment		$ 890,000	$ 0
Gain on sale of equipment		600,000	0
R&D Expense
Restructuring Cost And Reserve [Line Items]
Restructuring charges		1,000,000	$ 0
Interest and Other Income
Restructuring Cost And Reserve [Line Items]
Gain on sale of equipment		600,000
Employee Severance and Benefits
Restructuring Cost And Reserve [Line Items]
Reduction in workforce \| Employee	10
Percentage of workforce reduced	50.00%
Restructuring charges		900,000
Legal and Facility Expenses
Restructuring Cost And Reserve [Line Items]
Restructuring charges		$ 100,000

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013	May 20, 2016
Commitments And Contingencies Disclosure [Line Items]
Operating lease expiration date	2018-02
Operating lease rent expense	$ 700,000	$ 700,000
License fees payable			$ 100,000
ISU Abxis \| Maximum
Commitments And Contingencies Disclosure [Line Items]
Potential milestone payments	2,000,000
Pfizer Inc \| Collaboration Agreement \| Maximum
Commitments And Contingencies Disclosure [Line Items]
Obligated to make milestone and royalty payments upon achievement of clinical, regulatory and commercial milestones	17,500,000
CMC ICOS Biologics, Inc.
Commitments And Contingencies Disclosure [Line Items]
Contractual obligation payments	$ 3,300,000			$ 3,800,000

Expected Future Lease Payments Under Operating Leases (Detail) $ in Thousands	Dec. 31, 2016 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2017	$ 745
2018	125
Total future minimum lease payments	$ 870

Convertible Notes - Related Parties - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Interest expense related to accrued interest and amortization of debt discount			$ 0	$ 1,500
Series F Convertible Preferred Stock
Debt Instrument [Line Items]
Convertible notes, shares issued upon conversion	1,511,723
Convertible preferred stock, warrants issued	372,045
Convertible Notes
Debt Instrument [Line Items]
Aggregate principal amount of convertible promissory notes issued and sold	$ 1,900
Convertible notes, accrued interest	$ 30	$ 30
Existing Stockholders \| Convertible Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount of convertible promissory notes issued and sold		$ 1,900
Convertible debt interest rate	12.00%	12.00%
Debt instrument maturity period	1 year

Redeemable Convertible Notes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Aug. 19, 2015
Debt Instrument [Line Items]
Conversion of convertible notes in to common stock, value		$ 117,647,000
Gain on extinguishment of redeemable convertible notes	$ 99,000	52,000
Convertible Notes
Debt Instrument [Line Items]
Convertible notes, total outstanding principal amount			$ 37,000,000
Redeemable convertible notes, conversion per share price	$ 137.85
Convertible notes, maturity date	Feb. 19, 2018
Convertible notes, maturity period	30 months
Redeemable convertible notes, threshold trading days	10 days
Redeemable convertible notes, conversion feature	$ 1,500,000
Redeemable convertible notes, estimated fair value	37,100,000
Redeemable convertible notes, debt discount	1,400,000
Redeemable convertible notes, interest expense	0	$ 1,400,000
Redeemable convertible notes, redeemed	17,300,000
Conversion of convertible notes in to common stock, value	$ 300,000
Convertible Notes \| After Reverse Stock Split
Debt Instrument [Line Items]
Redeemable convertible notes, conversion per share price	$ 137.85

Stock Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for future grant	85,849
Options, Outstanding, Weighted Average Exercise Price	$ 128.25	$ 147.45	$ 134.40
Stock-based compensation expense	$ 635	$ 326
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%
Non Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Grants in Period	800	1,317
Options, Outstanding, Weighted Average Exercise Price	$ 20.40	$ 97.80
Stock-based compensation expense	$ 50	$ 40
Non Employee Stock Option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Period	1 year
Non Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Period	4 years
2004 Stock Plan \| Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%
Unrecognized employee stock based compensation expense	$ 1,000
Unrecognized employee stock based compensation expense, period for recognition	2 years 6 months 26 days
2015 Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for future grant	85,849
Shares remaining outstanding	140,990
Merger Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock exchange rate	3.82%

Summary of Stock-Based Compensation Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 635	$ 326
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	185	95
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 450	$ 231

Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Expected term	6 years 1 month 21 days	5 years 6 months 22 days
Expected volatility	76.59%	68.64%
Risk-free interest rate	1.53%	1.34%
Expected dividend yield	0.00%	0.00%
Non Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Expected term	9 years 8 months 27 days	5 years 7 months 21 days
Expected volatility	101.12%	69.98%
Risk-free interest rate	2.39%	1.30%

Summary of Option Activity (Detail) - USD ($)

12 Months Ended

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Number of Shares Underlying Outstanding Options

Number of Shares Underlying Outstanding Options, Beginning Balance

146,634

16,683

Number of Shares Underlying Outstanding Options, Options assumed in merger

^[1]

94,721

Number of Shares Underlying Outstanding Options, Options granted

14,706

45,039

Number of Shares Underlying Outstanding Options, Options exercised

(254)

Number of Shares Underlying Outstanding Options, Fractional shares written off in connection with the merger

^[1]

(4)

Number of Shares Underlying Outstanding Options, Options forfeited

(6,573)

(2,436)

Number of Shares Underlying Outstanding Options, Options canceled

(13,773)

(7,119)

Number of Shares Underlying Outstanding Options, Ending Balance

140,990

146,634

16,683

Number of Shares Underlying Outstanding Options, Exercisable- December 31, 2016

106,472

Number of Shares Underlying Outstanding Options, Vested and expected to vest - December 31, 2016

68,977

Shares Available to be granted - December 31, 2016

85,849

Weighted- Average Exercise Price

Weighted- Average Exercise Price, Beginning Balance

$ 147.45

$ 134.40

Weighted- Average Exercise Price, Options assumed in merger

^[1]

227.40

Weighted- Average Exercise Price, Options exercised, Options granted

23.70

44.70

Weighted- Average Exercise Price, Options exercised

50.70

Weighted- Average Exercise Price, Options forfeited

64.95

127.20

Weighted- Average Exercise Price, Options canceled

259.05

708.00

Weighted- Average Exercise Price, Ending Balance

128.25

$ 147.45

$ 134.40

Weighted- Average Exercise Price, Exercisable - December 31, 2016

152.70

Weighted- Average Exercise Price, Vested and expected to vest - December 31, 2016

$ 74.70

Weighted Average Remaining Contractual Term

Weighted Average Remaining Contractual Term, Outstanding Balance

3 years 11 months 5 days

5 years 6 months 4 days

Weighted Average Remaining Contractual Term, Options assumed in merger

^[1]

4 years 4 days

Weighted Average Remaining Contractual Term, Options granted

9 years 9 months 22 days

Weighted Average Remaining Contractual Term, Exercisable — December 31, 2016

2 years 3 months 11 days

Weighted Average Remaining Contractual Term, Vested and expected to vest — December 31, 2016

7 years 1 month 2 days

Aggregate Intrinsic Value

Aggregate Intrinsic Value, Outstanding

$ 15,524,910

[1]

Summary of Option Activity (Parenthetical) (Detail)
$ in Thousands

12 Months Ended

Dec. 31, 2016

USD ($)

Dec. 31, 2015

Installment

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of Shares Underlying Outstanding Options, Options assumed in merger

^[1]

94,721

Aggregate fractional shares written off in merger

^[1]

Restricted Stock

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of restricted stock awards, assumed in merger

190

Number of Shares Underlying Outstanding Options, Options assumed in merger

94,721

Number of equal annual installments | Installment

Aggregate fractional shares written off in merger

Total stock based compensation | $

$ 20

[1]

Reconciliation of Statutory Federal Income Tax (benefit) Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Tax at statutory federal rate	34.00%	34.00%
State Tax (benefit)—net of federal benefit	1.12%	1.33%
Permanent differences	7.95%	(8.00%)
R&D Credits	3.16%	11.59%
Derecognition due to Sec. 382 and 383 Limitations	0.00%	(240.87%)
Change in Valuation Allowance	(46.66%)	204.17%
Other	0.43%	(2.22%)

Components of Company's Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Accruals and reserves	$ 1,137	$ 1,285
Net Operating Loss Carry forwards	25,944	17,650
R&D Tax Credit Carry forwards	3,174	2,625
Fixed and intangible assets	114	95
Valuation Allowance	$ (30,369)	$ (21,655)

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2007
Income Tax [Line Items]
Gross federal R&D tax credit-related deferred tax assets derecognized	$ 5,600,000
Unrecognized tax benefit	1,539,000	$ 1,314,000	$ 2,570,000
Tax-related penalties or interest recognized	0	$ 0
Federal Income Tax
Income Tax [Line Items]
Net operating loss carryforwards	$ 68,300,000			$ 76,300,000
Net operating loss carry forwards expire period	Dec. 31, 2025
Tax credit carryforwards available to offset future federal tax liabilities	$ 500,000
Tax credit carryforward, expire period	Dec. 31, 2024
Net operating loss carryforward,derecognized				$ 25,900,000
State Income Tax
Income Tax [Line Items]
Net operating loss carryforwards	$ 46,600,000
Net operating loss carry forwards expire period	Dec. 31, 2017
Tax credit carryforwards available to offset future federal tax liabilities	$ 5,600,000
CALIFORNIA
Income Tax [Line Items]
Net operating loss carryforwards	56,100,000
Net operating loss carryforward,derecognized	$ 3,300,000

Unrecognized tax benefit (Detail) - USD ($) $ in Thousands	12 Months Ended
Unrecognized tax benefit (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Beginning Balance	$ 1,314	$ 2,570
Increase/(Decrease) of unrecognized tax benefits taken in prior years	6	(1,347)
Increase/(Decrease) of unrecognized tax benefits related to current year	219	91
Ending Balance	$ 1,539	$ 1,314

Collaborations - Additional Information (Detail)				12 Months Ended
Collaborations - Additional Information (Detail)	Apr. 02, 2015	Aug. 20, 2013 USD ($) Payment	Jun. 16, 2013 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contract revenue				$ 399,000	$ 1,750,000
Pfizer Inc
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Number of Non-refundable annual license maintenance payments \| Payment		2
Non-refundable annual license maintenance payments		$ 1,500,000
License maintenance payable period one		Aug. 01, 2014
License maintenance payable period two		Aug. 01, 2013
Effective termination notice period	60 days
Contract revenue				0	1,300,000
Deferred revenue				0	0
Pfizer Inc \| Collaboration Agreement \| Maximum
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contingent cash payments upon achievement of clinical, regulatory and commercial milestones				17,500,000
ISU Abxis
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contract revenue				400,000	400,000
Deferred revenue				$ 300,000	$ 700,000
Deferred revenue recognition period				4 years
ISU Abxis \| Up Front Payment
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Amount received for research and development process			$ 1,750,000

Detail of Other Income, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Other Income And Expenses [Abstract]
Gain on sale of NNR assets	$ 1,674
Change in derivative liability	1,156	$ 387
Gain on sale of fixed assets	557	(15)
Other Income, net	86	131
Total Other Income, net	$ 3,473	$ 518

Common Stock - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 28, 2017	Mar. 16, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, value of shares issued under sales agreement	$ 1,000			$ 1,000
Net proceeds from sale of common stock	$ 958,000
Capital on Demand Sales Agreement with Jones Trading Institutional Services LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued under sales agreement	39,743
Common stock weighted average selling price	$ 25.08
Net proceeds from sale of common stock	$ 1,000,000
Offering costs	100,000
Costs against additional paid-in capital	$ 30,000
Capital on Demand Sales Agreement with Jones Trading Institutional Services LLC \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, value of shares issued under sales agreement			$ 6,500,000
Capital on Demand Sales Agreement with Jones Trading Institutional Services LLC \| Maximum \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for sale		$ 3,600,000

Basic and Diluted Net Loss Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net loss, basic and diluted	$ (16,945)	$ (14,762)
Weighted-average number of shares used in computing net loss per share, basic and diluted	779,166	295,272
Net loss per share, basic and diluted	$ (21.75)	$ (49.99)

Anti-dilutive Security not Included In Diluted per Share Calculations (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	293,796	403,572
Options To Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	140,990	146,726
Common Stock Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	12,063	12,063
Redeemable Convertible Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	140,743	244,783