Viracta Therapeutics (VIRX) 10-Q 30 Jul 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Trading Symbol	SNSS
Entity Registrant Name	SUNESIS PHARMACEUTICALS INC
Entity Central Index Key	1,061,027
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		75,470,899

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	[1]
Current assets:
Cash and cash equivalents	$ 20,302	$ 22,186
Marketable securities	19,254	20,795
Prepaids and other current assets	1,165	1,223
Total current assets	40,721	44,204
Property and equipment, net	19	42
Total assets	40,740	44,246
Current liabilities:
Accounts payable	2,282	3,177
Accrued clinical expense	2,249	3,112
Accrued compensation	1,245	2,287
Other accrued liabilities	4,072	3,087
Current portion of deferred revenue	3,418	3,418
Current portion of notes payable	3,253	9,257
Warrant liability	1,765	3,543
Total current liabilities	18,284	27,881
Non-current portion of deferred revenue	854	$ 2,563
Non-current portion of notes payable	$ 4,421
Commitments
Stockholders’ equity:
Common stock	$ 7	$ 7
Additional paid-in capital	557,953	536,499
Accumulated other comprehensive loss	(5)	(7)
Accumulated deficit	(540,774)	(522,697)
Total stockholders’ equity	17,181	13,802
Total liabilities and stockholders’ equity	$ 40,740	$ 44,246
[1]	The condensed consolidated balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue:
License and other revenue	$ 854	$ 1,989	$ 1,708	$ 3,984
Total revenues	854	1,989	1,708	3,984
Operating expenses:
Research and development	6,302	7,206	10,814	14,758
General and administrative	5,175	6,387	10,286	9,804
Total operating expenses	11,477	13,593	21,100	24,562
Loss from operations	(10,623)	(11,604)	(19,392)	(20,578)
Interest expense	(233)	(470)	(472)	(1,017)
Other income (expense), net	1,907	293	1,787	(4,759)
Net loss	(8,949)	(11,781)	(18,077)	(26,354)
Unrealized gain (loss) on available-for-sale securities		(11)	2	(4)
Comprehensive loss	(8,949)	(11,792)	(18,075)	(26,358)
Net loss:
Basic	(8,949)	(11,781)	(18,077)	(26,354)
Diluted	$ (10,816)	$ (12,114)	$ (18,077)	$ (26,354)
Shares used in computing net loss per common share:
Basic	72,513	60,246	70,090	58,291
Diluted	72,525	61,895	70,090	58,291
Net loss per common share:
Basic	$ (0.12)	$ (0.20)	$ (0.26)	$ (0.45)
Diluted	$ (0.15)	$ (0.20)	$ (0.26)	$ (0.45)

CONDENSED CONSOLIDATED STATEME4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014
Cash flows from operating activities
Net loss	$ (18,077)		$ (26,354)
Adjustments to reconcile loss to net cash used in operating activities:
Stock-based compensation expense	3,332		2,770
Depreciation and amortization	22		11
Amortization of debt discount and debt issuance costs	75		217
Change in fair value of warrant liability	(1,778)		4,604
Changes in operating assets and liabilities:
Prepaids and other assets	54		57
Accounts payable	(895)		(440)
Accrued clinical expense	(863)		(812)
Accrued compensation	(1,042)		(431)
Other accrued liabilities	1,074		2,730
Deferred revenue	(1,709)		(3,978)
Net cash used in operating activities	(19,807)		(21,626)
Cash flows from investing activities
Purchases of property and equipment			(23)
Purchases of marketable securities	(18,927)		(32,934)
Proceeds from maturities of marketable securities	20,470		25,320
Net cash provided by (used in) investing activities	1,543		(7,637)
Cash flows from financing activities
Principal payments on notes payable	(1,642)		(4,573)
Proceeds from issuance of common stock and warrants in underwritten offering, net			40,012
Proceeds from issuance of common stock through controlled equity offering facilities, net	17,675		4,726
Proceeds from exercise of warrants, stock options and stock purchase rights	347		738
Net cash provided by financing activities	16,380		40,903
Net (decrease) increase in cash and cash equivalents	(1,884)		11,640
Cash and cash equivalents at beginning of period	22,186	[1]	15,121
Cash and cash equivalents at end of period	20,302		$ 26,761
Supplemental disclosure of non-cash activities
Fair value of warrants issued in connection with notes payable	$ 100
[1]	The condensed consolidated balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.

Company Overview

Company Overview	6 Months Ended
	Jun. 30, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Company Overview	1. Company Overview Description of Business Sunesis Pharmaceuticals, Inc. (the “Company” or “Sunesis”) was incorporated in the state of Delaware on February 10, 1998, and its facilities are located in South San Francisco, California. Sunesis is a biopharmaceutical company focused on the development and commercialization of new oncology therapeutics for the treatment of solid and hematologic cancers. The Company’s primary activities since incorporation have been conducting research and development internally and through corporate collaborators, in-licensing and out-licensing pharmaceutical compounds and technology, conducting clinical trials and raising capital. In October 2014, the Company announced the results of a Phase 3, multi-national, randomized, double-blind, placebo-controlled, clinical trial of vosaroxin in combination with cytarabine in patients with relapsed or refractory acute myeloid leukemia (the “VALOR trial”). The trial did not meet its primary endpoint of demonstrating a statistically significant improvement in overall survival. Based upon the results of other predefined analyses of the data and feedback from meetings held in June 2015 with its European Rapporteur and Co-Rapporteur, who are two appointed members of the European Medicines Agency (“EMA”) Committee of Human Medicinal Products, Sunesis plans to file a marketing authorization application (“MAA”) with the EMA as soon as practicable. Based upon a meeting with the U.S. Food and Drug Administration (“FDA”) held in July 2015, the FDA recommended that the Company provide additional clinical evidence prior to any regulatory filing in the U.S. As a result, the Company plans to evaluate regulatory and clinical strategies with the goal of gaining future marketing approval in the U.S Significant Risks and Uncertainties The Company has incurred significant losses and negative cash flows from operations since its inception, and as of June 30, 2015, had cash, cash equivalents and marketable securities totaling $39.6 million and an accumulated deficit of $540.8 million. The Company will need to raise substantial additional capital to pursue a regulatory strategy for the potential commercialization of QINPREZO TM its product candidate for the potential treatment of acute myeloid leukemia, However, the Company does not know whether additional funding will be available on acceptable terms, or at all. If the Company is unable to raise required funding on acceptable terms or at all, it will need to reduce operating expenses, enter into a collaboration or other similar arrangement with respect to development and/or commercialization rights to vosaroxin, outlicense intellectual property rights to vosaroxin or our other development programs, sell unsecured assets, or a combination of the above, or be forced to delay or reduce the scope of its vosaroxin development program, potentially including any regulatory filings related to the VALOR trial, and/or limit or cease its operations. Concentrations of Credit Risk In accordance with its investment policy, the Company invests cash that is not currently being used for operational purposes. The policy allows for the purchase of low risk debt securities issued by: (a) the United States and certain European governments and government agencies, and (b) highly rated banks and corporations, denominated in U.S. dollars, Euros or British pounds, subject to certain concentration limits. The policy limits maturities of securities purchased to no longer than 24 months and the weighted average maturity of the portfolio to 12 months. Management believes these guidelines ensure both the safety and liquidity of any investment portfolio the Company may hold. Financial instruments that potentially subject the Company to concentrations of credit risk generally consist of cash, cash equivalents and marketable securities. The Company is exposed to credit risk in the event of default by the institutions holding its cash, cash equivalents and any marketable securities to the extent of the amounts recorded in the balance sheets.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The financial statements include all adjustments (consisting only of normal recurring adjustments) that management believes are necessary for a fair presentation of the periods presented. The balance sheet as of December 31, 2014 was derived from the audited financial statements as of that date. These interim financial results are not necessarily indicative of results to be expected for the full year or any other period. These unaudited condensed consolidated financial statements and the notes accompanying them should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers In August Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern which will require a reporting entity to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the reporting entity's ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Sunesis Europe Limited, a United Kingdom corporation, and Sunesis Pharmaceuticals (Bermuda) Ltd., a Bermuda corporation, as well as a Bermuda limited partnership, Sunesis Pharmaceuticals International LP. All intercompany balances and transactions have been eliminated in consolidation. Segment Reporting Management has determined that the Company operates as a single reportable segment. Significant Estimates and Judgments The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s consolidated financial statements and accompanying notes thereto. Actual results could differ materially from these estimates. Estimates, assumptions and judgments made by management include those related to the valuation of equity and related instruments, revenue recognition, stock-based compensation and clinical trial accounting. Cash Equivalents and Marketable Securities Invoices for certain services provided to the Company are denominated in foreign currencies. To manage the risk of future movements in foreign exchange rates that would affect such amounts, the Company may purchase certain European currencies or highly-rated investments denominated in those currencies, subject to similar criteria as for other investments defined in the Company’s investment policy. There is no guarantee that the related gains and losses will substantially offset each other, and the Company may be subject to significant exchange gains or losses as currencies fluctuate from quarter to quarter. To date, the Company has purchased Euros and Euro-denominated obligations of foreign governments and corporate debt. As of June 30, 2015 and December 31, 2014, the Company held cash and investments denominated in Euros with an aggregate fair value of $0.7 million and $0, respectively. Any cash, cash equivalent and marketable securities balances denominated in foreign currencies are recorded at their fair value based on the current exchange rate as of each balance sheet date. The resulting exchange gains or losses and those from amounts payable for services originally denominated in foreign currencies are recorded in other income (expense), net in the statements of operations and comprehensive loss. Fair Value Measurements The Company measures cash equivalents, marketable securities and warrant liabilities at fair value on a recurring basis using the following hierarchy to prioritize valuation inputs, in accordance with applicable GAAP: Level 1 - quoted prices (unadjusted) in active markets for identical assets and liabilities that can be accessed at the measurement date. Level 2 - inputs other than quoted prices included within Level 1 that are observable, either directly or indirectly. Level 3 - unobservable inputs. The Company’s Level 2 valuations of marketable securities are generally derived from independent pricing services based upon quoted prices in active markets for similar securities, with prices adjusted for yield and number of days to maturity, or based on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets. The fair value of the Company’s liability for warrants issued in connection with an underwritten offering completed in October 2010 (the “2010 Offering”) is determined using the Black-Scholes model, which requires inputs such as the expected term of the warrants, share price volatility, expected dividend yield and risk-free interest rate. As some of these inputs are unobservable, and require significant analysis and judgment to measure, these variables are classified as Level 3. The Company does not measure cash, prepayments, accounts payable, accrued liabilities, deferred revenue and notes payable at fair value, as their carrying amounts approximated their fair value as of June 30, 2015 and December 31, 2014.

Loss per Common Share

Loss per Common Share	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Loss per Common Share	3. Loss per Common Share Basic loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding for the period. Diluted loss per common share is computed by dividing (a) net loss, less any anti-dilutive amounts recorded during the period for the change in the fair value of warrant liabilities, by (b) the weighted-average number of common shares outstanding for the period plus dilutive potential common shares as determined using the treasury stock method for options and warrants to purchase common stock. The following table sets forth the computation of basic and diluted loss per common share for the periods presented (in thousands, except per share amounts): Three months ended June 30, Six months ended June 30, 2015 2014 2015 2014 Numerator: Net loss—basic $ (8,949 ) $ (11,781 ) $ (18,077 ) $ (26,354 ) Adjustment for change in fair value of warrant liability (1,867 ) (333 ) — — Net loss—diluted $ (10,816 ) $ (12,114 ) $ (18,077 ) $ (26,354 ) Denominator: Weighted-average common shares outstanding—basic 72,513 60,246 70,090 58,291 Dilutive effect of warrants 12 1,649 — — Weighted-average common shares outstanding—diluted 72,525 61,895 70,090 58,291 Net loss per common share: Basic $ (0.12 ) $ (0.20 ) $ (0.26 ) $ (0.45 ) Diluted $ (0.15 ) $ (0.20 ) $ (0.26 ) $ (0.45 ) The following table represents the potential common shares issuable pursuant to outstanding securities as of the related period end dates that were excluded from the computation of diluted loss per common share because their inclusion would have had an anti-dilutive effect (in thousands): Three months ended June 30, Six months ended June 30, 2015 2014 2015 2014 Warrants to purchase shares of common stock 9,040 16,139 11,960 19,171 Options to purchase shares of common stock 10,422 9,321 10,422 9,321 Restricted stock units 233 — 233 — Outstanding securities not included in calculations 19,695 25,460 22,615 28,492

Financial Instruments

Financial Instruments	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Financial Instruments	4. Financial Instruments Financial Assets The following tables summarize the estimated fair value of the Company’s financial assets measured on a recurring basis as of the dates indicated, which were comprised solely of available-for-sale marketable securities with remaining contractual maturities of one year or less (in thousands): June 30, 2015 Input Level Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds Level 1 $ 7,422 $ — $ — $ 7,422 U.S. certificates of deposit Level 1 8,246 — — 8,246 U.S. corporate debt obligations Level 2 8,447 — (4 ) 8,443 U.S. commercial paper Level 2 3,498 — (1 ) 3,497 Total available-for-sale securities 27,613 — (5 ) 27,608 Less amounts classified as cash equivalents (8,354 ) — — (8,354 ) Amounts classified as marketable securities $ 19,259 $ — $ (5 ) $ 19,254 December 31, 2014 Input Level Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds Level 1 $ 9,287 $ — $ — $ 9,287 U.S. certificates of deposit Level 1 6,360 — — 6,360 U.S. corporate debt obligations Level 2 11,789 — (7 ) 11,782 U.S. commercial paper Level 2 2,898 — — 2,898 Total available-for-sale securities 30,334 — (7 ) 30,327 Less amounts classified as cash equivalents (9,532 ) — — (9,532 ) Amounts classified as marketable securities $ 20,802 $ — $ (7 ) $ 20,795 The following table summarizes the available-for-sale securities that were in an unrealized loss position as of the date indicated, having been in such a position for less than 12 months, and none having been deemed to be other-than-temporarily impaired (in thousands): June 30, 2015 Gross Unrealized Losses Estimated Fair Value U.S. corporate debt obligations $ 4 $ 7,274 U.S. commercial paper 1 2,498 $ 5 $ 9,772 No significant facts or circumstances have arisen to indicate that there has been any deterioration in the creditworthiness of the issuers of these securities. The gross unrealized losses are not considered to be significant and have generally been for relatively short durations. The Company does not intend to sell these securities before maturity and it is not likely that they will need to be sold prior to the recovery of their amortized cost basis. There were no sales of available-for-sale securities during either the six months ended June 30, 2015 or 2014. Financial Liabilities The following table summarizes the inputs and assumptions and estimated fair value of the Company’s financial liabilities measured at fair value on a recurring basis as of the dates indicated, which were comprised solely of a liability for warrants issued in connection with the 2010 Offering: June 30, 2015 December 31, 2014 Inputs and assumptions: Fair market value of Company’s common stock $ 3.01 $ 2.55 Exercise price $ 2.52 $ 2.52 Expected term (years) 0.3 0.8 Expected volatility 52.2 % 144.9 % Risk-free interest rate 0.02 % 0.19 % Expected dividend yield 0.00 % 0.00 % Fair value: Estimated fair value per warrant share $ 0.60 $ 1.21 Shares underlying outstanding warrants classified as liabilities (in thousands) 2,920 2,920 Total estimated fair value of outstanding warrants (in thousands) $ 1,765 $ 3,543 The warrants have been classified as a liability on the Company’s balance sheet due to the potential for the warrants to be settled in cash upon the occurrence of certain transactions specified in the warrant agreements. At each balance sheet date, the estimated fair value of the outstanding warrants is determined using the Black-Scholes model and recorded to the balance sheet, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss, and the fair value of warrant exercises transferred to additional paid-in capital. During the six months ended June 30, 2015, no warrants to purchase shares of common stock issued in connection with the 2010 Offering were exercised. The Black-Scholes model requires Level 3 inputs such as the expected term of the warrants and share price volatility. These inputs are subjective and generally require significant analysis and judgment to develop. Any changes in these inputs could result in a significantly higher or lower fair value measurement. The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities for the period indicated (in thousands): Warrant Liability Balance as of December 31, 2014 $ 3,543 Change in fair value of warrant liability (1,778 ) Exercise of warrants — Balance as of June 30, 2015 $ 1,765

Royalty Agreement

Royalty Agreement	6 Months Ended
	Jun. 30, 2015
Revenue Recognition [Abstract]
Royalty Agreement	5. Royalty Agreement In March 2012, the Company entered into a Revenue Participation Agreement (the “Royalty Agreement”), with RPI Finance Trust (“RPI”), an entity related to Royalty Pharma. In September 2012, pursuant to the provisions of the Royalty Agreement, RPI made a $25.0 million cash payment to the Company. The payment, less $3.1 million representing the fair value of the warrants granted under the arrangement, was initially classified as deferred revenue and is being amortized to revenue over the related performance period. Revenue participation right payments will be made to RPI when and if vosaroxin is commercialized, at a rate of 6.75% of net sales of vosaroxin, on a product-by-product and country-by-country basis world-wide through the later of: (a) the expiration of the last to expire of certain specifically identified patents; (b) 10 years from the date of first commercial sale of such product in such country; or (c) the expiration of all applicable periods of data, market or other regulatory exclusivity in such country with respect to such product.

License Agreements

License Agreements	6 Months Ended
	Jun. 30, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
License Agreements	6. License Agreements Biogen Idec In December 2013, the Company entered into a second amended and restated collaboration agreement with Biogen Idec MA, Inc. (the “Biogen Idec 2nd ARCA”), to provide the Company with an exclusive worldwide license to develop, manufacture and commercialize SNS-062, a BTK inhibitor synthesized under the first amended and restated collaboration agreement with Biogen Idec (the “Biogen Idec 1st ARCA”), solely for oncology indications. The Company may be required to make a $2.5 million milestone payment depending on its development of SNS-062 and royalty payments depending on related product sales of SNS-062. All other of Sunesis’ rights and obligations contained in the Biogen Idec 1st ARCA remain unchanged, except that potential future royalty payments to Sunesis were reduced to equal those amounts due to Biogen Idec for potential future sales of SNS-062. Millennium In March 2011, Millennium Pharmaceuticals, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited (“Millennium”) purchased and exclusively licensed Biogen Idec’s rights to a PDK1 inhibitor program and a pan-Raf inhibitor program which were both originally developed through a collaboration agreement between Sunesis and Biogen Idec. In January 2014, the Company entered into an amended and restated license agreement with Millennium (the “Amended Millennium Agreement”), to provide the Company with an exclusive worldwide license to develop and commercialize preclinical inhibitors of PDK1. In connection with the execution of the Amended Millennium Agreement, the Company paid an upfront fee and may be required to make up to $9.2 million in pre-commercialization milestone payments depending on its development of PDK1 inhibitors and royalty payments depending on related product sales, if any. With respect to the pan-Raf inhibitor program, the Company may in the future receive up to $57.5 million in pre-commercialization event-based payments related to the development by Millennium of the first two indications for each of the licensed products directed against the Raf target and royalty payments depending on related product sales. Under this program, Millennium is currently conducting Phase 1 clinical studies of an oral investigative drug, MLN2480.

Notes Payable

Notes Payable	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Notes Payable	7. Notes Payable In October 2011, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation (collectively, the “Lenders”), under which the Company could borrow up to $25.0 million in two tranches (the “Loan Facility”). The first tranche of $10.0 million was funded upon closing of the transaction in October 2011, and the second tranche of $15.0 million was drawn by the Company in September 2012. In connection with the Loan Agreement, the Lenders were granted a perfected first priority security interest in substantially all of the Company’s assets, other than intellectual property. The interest rates for the first and second tranche are 8.95% and 9.00% per annum, respectively. Payments under the Loan Agreement are monthly in arrears and were interest-only until February 1, 2013, and were to be followed by 32 equal monthly payments of principal and interest from March 1, 2013 to the original maturity date of October 1, 2015. In addition, a final payment equal to $937,500 was to be due on October 1, 2015, or such earlier date as specified in the Loan Agreement. On February 27, 2015, the Company entered into an amendment (the “Amendment”), to the Loan Agreement with the Lenders. The Amendment modifies the loan repayment terms to be interest-only from March 1, 2015 to February 1, 2016, followed by eight equal monthly payments of principal and interest through the new maturity date of October 1, 2016. In addition, the final payment was increased to $1,162,500, and will become due on the new maturity date, or such earlier date specified in the Loan Agreement. If the Company repays all or a portion of the loan prior to February 29, 2016 as part of a refinancing with another lender, a prepayment fee equal to 2% of the then outstanding principal balance will be due to the Lenders. The remaining balance of the final payment that has yet to be expensed is being accreted as interest expense using the effective interest method In connection with the Amendment, the Lenders were issued five-year warrants to purchase an aggregate of up to 61,467 shares of the Company’s common stock at a per share exercise price of $2.22. The fair value of these warrants was estimated to be $0.1 million using the Black-Scholes valuation model. The fair value of these warrants was recorded at issuance as a debt discount within notes payable and an increase to additional paid-in capital on the Company’s balance sheet. The balance of the debt discount, including the fair value of these warrants, is being amortized as interest expense over the remaining term of the Loan Agreement, as amended, using the effective interest method. The weighted average annual effective interest rate of the notes payable under the revised amortization schedule is 13.8%. Aggregate future minimum payments due under the Loan Agreement as of June 30, 2015 were as follows (in thousands): Year ending December 31, Total 2015 $ 306 2016 7,154 Total minimum payments 7,460 Less amount representing interest (640 ) Notes payable, gross 6,820 Unamortized discount on notes payable (114 ) Accretion of final payment 968 Notes payable, balance 7,674 Less current portion of notes payable (3,253 ) Non-current portion of notes payable $ 4,421

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity Controlled Equity Offerings In August 2011, the Company entered into a Controlled Equity Offering SM During the six months ended June 30, 2015, the Company sold 6,834,978 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.65 per share for gross proceeds of $18.1 million and net proceeds of $17.7 million, after deducting Cantor’s commission. As of June 30, 2015, $18.7 million of common stock remained available to be sold under this facility, subject to certain conditions as specified in the Sales Agreement, as amended. In July 201 5 124,100 3.70 0.5 0.4 5 18.2

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation Employee stock-based compensation expense is calculated based on the grant-date fair value of awards ultimately expected to vest, and is recorded on a straight-line basis over the vesting period of the awards. Forfeitures are estimated at the time of grant, based on historical option cancellation information, and revised in subsequent periods if actual forfeitures differ from those estimates. The following table summarizes stock-based compensation expense related to the Company’s stock-based awards for the periods indicated (in thousands): Three months ended June 30, Six months ended June 30, 2015 2014 2015 2014 Research and development $ 595 $ 519 $ 1,293 $ 978 General and administrative 718 837 1,876 1,564 Employee stock-based compensation expense 1,313 1,356 3,169 2,542 Non-employee stock-based compensation expense 55 108 163 228 Total stock-based compensation expense $ 1,368 $ 1,464 $ 3,332 $ 2,770

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	10. Subsequent Events In July 201 5 124,100 3.70 0.5 0.4 See Note 8 for further details.

Summary of Significant Accoun15

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The financial statements include all adjustments (consisting only of normal recurring adjustments) that management believes are necessary for a fair presentation of the periods presented. The balance sheet as of December 31, 2014 was derived from the audited financial statements as of that date. These interim financial results are not necessarily indicative of results to be expected for the full year or any other period. These unaudited condensed consolidated financial statements and the notes accompanying them should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers In August Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern which will require a reporting entity to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the reporting entity's ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Sunesis Europe Limited, a United Kingdom corporation, and Sunesis Pharmaceuticals (Bermuda) Ltd., a Bermuda corporation, as well as a Bermuda limited partnership, Sunesis Pharmaceuticals International LP. All intercompany balances and transactions have been eliminated in consolidation.
Segment Reporting	Segment Reporting Management has determined that the Company operates as a single reportable segment.
Significant Estimates and Judgments	Significant Estimates and Judgments The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s consolidated financial statements and accompanying notes thereto. Actual results could differ materially from these estimates. Estimates, assumptions and judgments made by management include those related to the valuation of equity and related instruments, revenue recognition, stock-based compensation and clinical trial accounting.
Cash Equivalents and Marketable Securities	Cash Equivalents and Marketable Securities Invoices for certain services provided to the Company are denominated in foreign currencies. To manage the risk of future movements in foreign exchange rates that would affect such amounts, the Company may purchase certain European currencies or highly-rated investments denominated in those currencies, subject to similar criteria as for other investments defined in the Company’s investment policy. There is no guarantee that the related gains and losses will substantially offset each other, and the Company may be subject to significant exchange gains or losses as currencies fluctuate from quarter to quarter. To date, the Company has purchased Euros and Euro-denominated obligations of foreign governments and corporate debt. As of June 30, 2015 and December 31, 2014, the Company held cash and investments denominated in Euros with an aggregate fair value of $0.7 million and $0, respectively. Any cash, cash equivalent and marketable securities balances denominated in foreign currencies are recorded at their fair value based on the current exchange rate as of each balance sheet date. The resulting exchange gains or losses and those from amounts payable for services originally denominated in foreign currencies are recorded in other income (expense), net in the statements of operations and comprehensive loss.
Fair Value Measurements	Fair Value Measurements The Company measures cash equivalents, marketable securities and warrant liabilities at fair value on a recurring basis using the following hierarchy to prioritize valuation inputs, in accordance with applicable GAAP: Level 1 - quoted prices (unadjusted) in active markets for identical assets and liabilities that can be accessed at the measurement date. Level 2 - inputs other than quoted prices included within Level 1 that are observable, either directly or indirectly. Level 3 - unobservable inputs. The Company’s Level 2 valuations of marketable securities are generally derived from independent pricing services based upon quoted prices in active markets for similar securities, with prices adjusted for yield and number of days to maturity, or based on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets. The fair value of the Company’s liability for warrants issued in connection with an underwritten offering completed in October 2010 (the “2010 Offering”) is determined using the Black-Scholes model, which requires inputs such as the expected term of the warrants, share price volatility, expected dividend yield and risk-free interest rate. As some of these inputs are unobservable, and require significant analysis and judgment to measure, these variables are classified as Level 3. The Company does not measure cash, prepayments, accounts payable, accrued liabilities, deferred revenue and notes payable at fair value, as their carrying amounts approximated their fair value as of June 30, 2015 and December 31, 2014.

Loss per Common Share (Tables)

Loss per Common Share (Tables)	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Computation of Basic and Diluted Loss per Common Share	The following table sets forth the computation of basic and diluted loss per common share for the periods presented (in thousands, except per share amounts): Three months ended June 30, Six months ended June 30, 2015 2014 2015 2014 Numerator: Net loss—basic $ (8,949 ) $ (11,781 ) $ (18,077 ) $ (26,354 ) Adjustment for change in fair value of warrant liability (1,867 ) (333 ) — — Net loss—diluted $ (10,816 ) $ (12,114 ) $ (18,077 ) $ (26,354 ) Denominator: Weighted-average common shares outstanding—basic 72,513 60,246 70,090 58,291 Dilutive effect of warrants 12 1,649 — — Weighted-average common shares outstanding—diluted 72,525 61,895 70,090 58,291 Net loss per common share: Basic $ (0.12 ) $ (0.20 ) $ (0.26 ) $ (0.45 ) Diluted $ (0.15 ) $ (0.20 ) $ (0.26 ) $ (0.45 )
Schedule of Potential Common Shares Issuable Pursuant to Outstanding Securities Excluded from Computation of Diluted Loss per Common Share	The following table represents the potential common shares issuable pursuant to outstanding securities as of the related period end dates that were excluded from the computation of diluted loss per common share because their inclusion would have had an anti-dilutive effect (in thousands): Three months ended June 30, Six months ended June 30, 2015 2014 2015 2014 Warrants to purchase shares of common stock 9,040 16,139 11,960 19,171 Options to purchase shares of common stock 10,422 9,321 10,422 9,321 Restricted stock units 233 — 233 — Outstanding securities not included in calculations 19,695 25,460 22,615 28,492

Financial Instruments (Tables)

Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value of Company's Financial Assets Measured on Recurring Basis	The following tables summarize the estimated fair value of the Company’s financial assets measured on a recurring basis as of the dates indicated, which were comprised solely of available-for-sale marketable securities with remaining contractual maturities of one year or less (in thousands): June 30, 2015 Input Level Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds Level 1 $ 7,422 $ — $ — $ 7,422 U.S. certificates of deposit Level 1 8,246 — — 8,246 U.S. corporate debt obligations Level 2 8,447 — (4 ) 8,443 U.S. commercial paper Level 2 3,498 — (1 ) 3,497 Total available-for-sale securities 27,613 — (5 ) 27,608 Less amounts classified as cash equivalents (8,354 ) — — (8,354 ) Amounts classified as marketable securities $ 19,259 $ — $ (5 ) $ 19,254 December 31, 2014 Input Level Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds Level 1 $ 9,287 $ — $ — $ 9,287 U.S. certificates of deposit Level 1 6,360 — — 6,360 U.S. corporate debt obligations Level 2 11,789 — (7 ) 11,782 U.S. commercial paper Level 2 2,898 — — 2,898 Total available-for-sale securities 30,334 — (7 ) 30,327 Less amounts classified as cash equivalents (9,532 ) — — (9,532 ) Amounts classified as marketable securities $ 20,802 $ — $ (7 ) $ 20,795
Summary of Available-for-Sale Securities in Unrealized Loss Position	The following table summarizes the available-for-sale securities that were in an unrealized loss position as of the date indicated, having been in such a position for less than 12 months, and none having been deemed to be other-than-temporarily impaired (in thousands): June 30, 2015 Gross Unrealized Losses Estimated Fair Value U.S. corporate debt obligations $ 4 $ 7,274 U.S. commercial paper 1 2,498 $ 5 $ 9,772
Summary of Assumptions and Estimated Fair Value of Company's Financial Liabilities Measured on Recurring Basis	The following table summarizes the inputs and assumptions and estimated fair value of the Company’s financial liabilities measured at fair value on a recurring basis as of the dates indicated, which were comprised solely of a liability for warrants issued in connection with the 2010 Offering: June 30, 2015 December 31, 2014 Inputs and assumptions: Fair market value of Company’s common stock $ 3.01 $ 2.55 Exercise price $ 2.52 $ 2.52 Expected term (years) 0.3 0.8 Expected volatility 52.2 % 144.9 % Risk-free interest rate 0.02 % 0.19 % Expected dividend yield 0.00 % 0.00 % Fair value: Estimated fair value per warrant share $ 0.60 $ 1.21 Shares underlying outstanding warrants classified as liabilities (in thousands) 2,920 2,920 Total estimated fair value of outstanding warrants (in thousands) $ 1,765 $ 3,543
Summary of Changes in Fair Value of Company's Level 3 Financial Liabilities	The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities for the period indicated (in thousands): Warrant Liability Balance as of December 31, 2014 $ 3,543 Change in fair value of warrant liability (1,778 ) Exercise of warrants — Balance as of June 30, 2015 $ 1,765

Notes Payable (Tables)

Notes Payable (Tables)	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Summary of Future Minimum Payments Under Loan Agreement	Aggregate future minimum payments due under the Loan Agreement as of June 30, 2015 were as follows (in thousands): Year ending December 31, Total 2015 $ 306 2016 7,154 Total minimum payments 7,460 Less amount representing interest (640 ) Notes payable, gross 6,820 Unamortized discount on notes payable (114 ) Accretion of final payment 968 Notes payable, balance 7,674 Less current portion of notes payable (3,253 ) Non-current portion of notes payable $ 4,421

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Expense Related to Company's Stock-Based Awards	The following table summarizes stock-based compensation expense related to the Company’s stock-based awards for the periods indicated (in thousands): Three months ended June 30, Six months ended June 30, 2015 2014 2015 2014 Research and development $ 595 $ 519 $ 1,293 $ 978 General and administrative 718 837 1,876 1,564 Employee stock-based compensation expense 1,313 1,356 3,169 2,542 Non-employee stock-based compensation expense 55 108 163 228 Total stock-based compensation expense $ 1,368 $ 1,464 $ 3,332 $ 2,770

Company Overview - Additional I

Company Overview - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	[1]
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Date of incorporation	Feb. 10, 1998
Cash, cash equivalents and marketable securities	$ 39,600
Accumulated deficit	$ 540,774	$ 522,697
Maturity limits period	24 months
Dollars weighted average maturity limit period	12 months
[1]	The condensed consolidated balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.

Summary of Significant Accoun21

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2015USD ($)Segment	Dec. 31, 2014USD ($)
Accounting Policies [Abstract]
Number of reportable segment | Segment	1
Fair value of investments denominated in Euros	$ 0.7	$ 0

Loss per Common Share - Computa

Loss per Common Share - Computation of Basic and Diluted Loss per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net loss—basic	$ (8,949)	$ (11,781)	$ (18,077)	$ (26,354)
Adjustment for change in fair value of warrant liability	(1,867)	(333)	1,778	(4,604)
Net loss—diluted	$ (10,816)	$ (12,114)	$ (18,077)	$ (26,354)
Denominator:
Weighted-average common shares outstanding—basic	72,513	60,246	70,090	58,291
Dilutive effect of warrants	12	1,649
Weighted-average common shares outstanding—diluted	72,525	61,895	70,090	58,291
Net loss per common share:
Basic	$ (0.12)	$ (0.20)	$ (0.26)	$ (0.45)
Diluted	$ (0.15)	$ (0.20)	$ (0.26)	$ (0.45)

Loss per Common Share - Schedul

Loss per Common Share - Schedule of Potential Common Shares Issuable Pursuant to Outstanding Securities Excluded from Computation of Diluted Loss per Common Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding securities not included in calculations	19,695	25,460	22,615	28,492
Warrants to purchase shares of common stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding securities not included in calculations	9,040	16,139	11,960	19,171
Options to purchase shares of common stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding securities not included in calculations	10,422	9,321	10,422	9,321
Restricted stock units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding securities not included in calculations	233		233

Financial Instruments - Fair Va

Financial Instruments - Fair Value of Company's Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	$ 27,613	$ 30,334
Available-for-sale securities, Gross Unrealized Losses	(5)	(7)
Available-for-sale securities, Estimated Fair Value	27,608	30,327
Less amounts classified as cash equivalents, Amortized Cost	(8,354)	(9,532)
Amounts classified as marketable securities, Amortized Cost	19,259	20,802
Amounts classified as marketable securities, Gross Unrealized Losses	(5)	(7)
Less amounts classified as cash equivalents, Estimated Fair Value	(8,354)	(9,532)
Amounts classified as marketable securities, Estimated Fair Value	19,254	20,795	[1]
Level 1 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	7,422	9,287
Available-for-sale securities, Estimated Fair Value	7,422	9,287
Level 1 [Member] | U.S. certificates of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	8,246	6,360
Available-for-sale securities, Estimated Fair Value	8,246	6,360
Level 2 [Member] | U.S. corporate debt obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	8,447	11,789
Available-for-sale securities, Gross Unrealized Losses	(4)	(7)
Available-for-sale securities, Estimated Fair Value	8,443	11,782
Level 2 [Member] | U.S. commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	3,498	2,898
Available-for-sale securities, Gross Unrealized Losses	(1)
Available-for-sale securities, Estimated Fair Value	$ 3,497	$ 2,898
[1]	The condensed consolidated balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.

Financial Instruments - Summary

Financial Instruments - Summary of Available-for-Sale Securities in Unrealized Loss Position (Detail) $ in Thousands	Jun. 30, 2015USD ($)
Schedule Of Available For Sale Securities [Line Items]
Gross Unrealized Losses	$ 5
Estimated Fair Value	9,772
U.S. corporate debt obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Gross Unrealized Losses	4
Estimated Fair Value	7,274
U.S. commercial paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Gross Unrealized Losses	1
Estimated Fair Value	$ 2,498

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Sales of available-for-sale securities	$ 0	$ 0
2010 Offering [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants exercised for cash, shares	0

Financial Instruments - Summa27

Financial Instruments - Summary of Assumptions and Estimated Fair Value of Company's Financial Liabilities Measured on Recurring Basis (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Inputs and assumptions:
Fair market value of Company’s common stock	$ 3.01	$ 2.55
Exercise price	$ 2.52	$ 2.52
Expected term (years)	3 months 18 days	9 months 18 days
Expected volatility	52.20%	144.90%
Risk-free interest rate	0.02%	0.19%
Expected dividend yield	0.00%	0.00%
Fair value:
Estimated fair value per warrant share	$ 0.60	$ 1.21
Shares underlying outstanding warrants classified as liabilities (in thousands)	2,920	2,920
Total estimated fair value of outstanding warrants (in thousands)	$ 1,765	$ 3,543	[1]
[1]	The condensed consolidated balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.

Financial Instruments - Summa28

Financial Instruments - Summary of Changes in Fair Value of Company's Level 3 Financial Liabilities (Detail) - Warrant Liability [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2015USD ($)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Beginning Balance	$ 3,543
Change in fair value of warrant liability	(1,778)
Ending Balance	$ 1,765

Royalty Agreement - Additional

Royalty Agreement - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Sep. 30, 2012	Jun. 30, 2015
Royalty Agreement [Line Items]
Revenue participation right payments, rate		6.75%
Revenue participation right payments, term		10 years from the date of first commercial sale
Maximum term of revenue participation right payments		10 years
Royalty Agreement [Member]
Royalty Agreement [Line Items]
Revenue participation right payments	$ 25
Fair value of warrants issued in connection with participation agreement	$ 3.1

License Agreements - Additional

License Agreements - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended
	Dec. 31, 2013	Jun. 30, 2015	Jan. 31, 2014
License Agreement Terms [Member] | Millennium License Agreements [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Potential pre-commercialization milestone payments payable			$ 9.2
Potential pre-commercialization payments receivable		$ 57.5
Biogen Idec [Member] | Development Events [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payment depending on development	$ 2.5

Notes Payable - Additional Info

Notes Payable - Additional Information (Detail) - Loan Agreement	Feb. 27, 2015USD ($)Loan$ / sharesshares	Jun. 30, 2015USD ($)TranchesInstallment	Sep. 30, 2012USD ($)	Sep. 19, 2012	Oct. 31, 2011USD ($)	Oct. 18, 2011
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 25,000,000
Number of tranches for maximum borrowing | Tranches		2
Number of installments | Installment		32
Line of credit facility final payment		$ 937,500
Notes payable [Member]
Debt Instrument [Line Items]
Loan Agreement monthly arrears and interest date		Mar. 1, 2013
Expiration date		Oct. 1, 2015
February 27, 2015 Loan Amendment
Debt Instrument [Line Items]
Line of credit facility final payment	$ 1,162,500
Expiration date	Oct. 1, 2016
Interest only period start date	Mar. 1, 2015
Interest only period end date	Feb. 1, 2016
Number of remaining principal payments | Loan	8
Prepayment penalty expiration date	Feb. 29, 2016
Percentage of penalty for prepaying loan before maturity	2.00%
Warrants Expiration Term	5 years
Number of warrants issued | shares	61,467
Warrants exercise price for shares | $ / shares	$ 2.22
Estimated fair value of warrants	$ 100,000
February 27, 2015 Loan Amendment | Weighted Average [Member]
Debt Instrument [Line Items]
Weighted average annual effective interest rate on notes payable, including amortization of debt discounts and accretion	13.80%
Tranche one [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 10,000,000
Date of Loan and Security Agreement		Oct. 31, 2011
Interest rate						8.95%
Tranche two [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 15,000,000
Line of credit facility remaining amount drawing date		Sep. 30, 2012
Interest rate				9.00%

Notes Payable - Summary of Futu

Notes Payable - Summary of Future Minimum Payments Under Loan Agreement (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	[1]
Debt Instrument [Line Items]
Notes payable, balance	$ 7,674
Less current portion of notes payable	(3,253)	$ (9,257)
Non-current portion of notes payable	4,421
Notes payable [Member]
Debt Instrument [Line Items]
2,015	306
2,016	7,154
Total minimum payments	7,460
Less amount representing interest	(640)
Notes payable, gross	6,820
Unamortized discount on notes payable	(114)
Accretion of final payment	$ 968
[1]	The condensed consolidated balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			6 Months Ended
	Jul. 31, 2015	Mar. 31, 2015	Apr. 30, 2013	Jun. 30, 2015	Jun. 30, 2014	Jul. 30, 2015	Aug. 31, 2011
Stockholders Equity [Line Items]
Proceeds from issuance of common stock through controlled equity offering facilities, net				$ 17,675	$ 4,726
Controlled Equity Offering Facilities [Member]
Stockholders Equity [Line Items]
Issuance of common stock, offering value							$ 20,000
Common stock sales agreement, date				2011-08
Issuance of common stock, remaining offering value				$ 18,700
Controlled Equity Offering Facilities [Member] | Subsequent Event
Stockholders Equity [Line Items]
Issuance of common stock, remaining offering value						$ 18,200
Controlled Equity Offering Facilities [Member] | Common Stock [Member]
Stockholders Equity [Line Items]
Common stock, shares sold				6,834,978
Price per common share				$ 2.65
Proceeds from issuance of common shares and warrants in offering, gross				$ 18,100
Proceeds from issuance of common stock through controlled equity offering facilities, net				$ 17,700
Controlled Equity Offering Facilities [Member] | Common Stock [Member] | Subsequent Event
Stockholders Equity [Line Items]
Common stock, shares sold	124,100
Price per common share	$ 3.70
Proceeds from issuance of common shares and warrants in offering, gross	$ 500
Proceeds from issuance of common stock through controlled equity offering facilities, net	$ 400
Additional Controlled Equity Offerings Facilities [Member] | April 2013
Stockholders Equity [Line Items]
Increase in aggregate controlled equity offering agreement as per amendment			$ 30,000
Issuance of common stock, commission percentage			3.00%
Common stock sales agreement amended, date				2013-04
Additional Controlled Equity Offerings Facilities [Member] | March 2015
Stockholders Equity [Line Items]
Increase in aggregate controlled equity offering agreement as per amendment		$ 30,000
Common stock sales agreement further amended, date				2015-03
Issuance of common stock, commission percentage, maximum		3.00%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Related to Company's Stock-Based Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	$ 1,368	$ 1,464	$ 3,332	$ 2,770
Employee stock-based compensation expense [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	1,313	1,356	3,169	2,542
Non-employee stock-based compensation expense [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	55	108	163	228
Research and development [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	595	519	1,293	978
General and administrative [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	$ 718	$ 837	$ 1,876	$ 1,564

Subsequent Events - Additional

Subsequent Events - Additional information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	6 Months Ended
	Jul. 31, 2015	Jun. 30, 2015	Jun. 30, 2014
Subsequent Event [Line Items]
Proceeds from issuance of common stock through controlled equity offering facilities, net		$ 17,675	$ 4,726
Controlled Equity Offering Facilities [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares sold		6,834,978
Price per common share		$ 2.65
Proceeds from issuance of common shares and warrants in offering, gross		$ 18,100
Proceeds from issuance of common stock through controlled equity offering facilities, net		$ 17,700
Subsequent Event | Controlled Equity Offering Facilities [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares sold	124,100
Price per common share	$ 3.70
Proceeds from issuance of common shares and warrants in offering, gross	$ 500
Proceeds from issuance of common stock through controlled equity offering facilities, net	$ 400