Viracta Therapeutics (VIRX) 10-Q10 Nov 142014 Q3 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2014	Oct. 31, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'SNSS	'
Entity Registrant Name	'SUNESIS PHARMACEUTICALS INC	'
Entity Central Index Key	'0001061027	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	61,949,147

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets:	'	'
Cash and cash equivalents	$20,807	$15,121	[1]
Marketable securities	23,912	24,172	[1]
Prepaids and other current assets	1,279	1,199	[1]
Total current assets	45,998	40,492	[1]
Property and equipment, net	53	23	[1]
Deposits and other assets	'	10	[1]
Total assets	46,051	40,525	[1]
Current liabilities:	'	'
Accounts payable	772	953	[1]
Accrued clinical expense	3,621	4,750	[1]
Accrued compensation	1,995	1,719	[1]
Other accrued liabilities	3,967	1,645	[1]
Current portion of deferred revenue	3,418	7,956	[1]
Current portion of notes payable	9,859	9,018	[1]
Warrant liability	13,673	7,931	[1]
Total current liabilities	37,305	33,972	[1]
Non-current portion of deferred revenue	3,418	3,712	[1]
Non-current portion of notes payable	1,713	9,025	[1]
Commitments	'	'	[1]
Stockholdersâ€™ equity (deficit):	'	'
Common stock	6	5	[1]
Additional paid-in capital	524,992	473,509	[1]
Accumulated other comprehensive loss	-9	-3	[1]
Accumulated deficit	-521,374	-479,695	[1]
Total stockholdersâ€™ equity (deficit)	3,615	-6,184	[1]
Total liabilities and stockholdersâ€™ equity (deficit)	$46,051	$40,525	[1]

[1]	The condensed consolidated balance sheet as of DecemberÂ 31, 2013 has been derived from the audited financial statements as of that date included in the Companyâ€™s Annual Report on FormÂ 10-K for the year ended DecemberÂ 31, 2013.

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenue:	'	'	'	'
License and other revenue	$854	$1,989	$4,838	$5,967
Total revenues	854	1,989	4,838	5,967
Operating expenses:	'	'	'	'
Research and development	6,939	6,957	21,697	22,008
General and administrative	7,226	2,807	17,030	8,140
Total operating expenses	14,165	9,764	38,727	30,148
Loss from operations	-13,311	-7,775	-33,889	-24,181
Interest expense	-391	-695	-1,408	-2,294
Other income (expense), net	-1,623	863	-6,382	-946
Net loss	-15,325	-7,607	-41,679	-27,421
Unrealized gain (loss) on available-for-sale securities	-2	9	-6	-29
Comprehensive loss	-15,327	-7,598	-41,685	-27,450
Net loss:	'	'	'	'
Basic	-15,325	-7,607	-41,679	-27,421
Diluted	($15,325)	($8,329)	($41,679)	($27,421)
Shares used in computing net loss per common share:	'	'	'	'
Basic	60,549	51,698	59,052	51,639
Diluted	60,549	53,271	59,052	51,639
Net loss per common share:	'	'	'	'
Basic	($0.25)	($0.15)	($0.71)	($0.53)
Diluted	($0.25)	($0.16)	($0.71)	($0.53)

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013
Cash flows from operating activities	'		'
Net loss	($41,679)		($27,421)
Adjustments to reconcile loss to net cash used in operating activities:	'		'
Stock-based compensation expense	4,405		2,897
Depreciation and amortization	18		16
Amortization of debt discount and debt issuance costs	300		488
Increase in fair value of warrant liability	6,238		984
Foreign exchange gain on marketable securities	'		-174
Changes in operating assets and liabilities:	'		'
Prepaids and other assets	-94		679
Accounts payable	-181		1,381
Accrued clinical expense	-1,129		-611
Accrued compensation	276		-163
Other accrued liabilities	2,512		169
Deferred revenue	-4,832		-5,967
Net cash used in operating activities	-34,166		-27,722
Cash flows from investing activities	'		'
Purchases of property and equipment	-48		'
Purchases of marketable securities	-37,947		-22,602
Proceeds from maturities of marketable securities	38,201		55,268
Net cash provided by investing activities	206		32,666
Cash flows from financing activities	'		'
Principal payments on notes payable	-6,937		-4,971
Proceeds from issuance of common stock and warrants in underwritten offering, net	40,024		'
Proceeds from issuance of common stock through controlled equity offering facilities, net	4,726		6,574
Proceeds from exercise of warrants, stock options and stock purchase rights	1,833		245
Net cash provided by financing activities	39,646		1,848
Net increase in cash and cash equivalents	5,686		6,792
Cash and cash equivalents at beginning of period	15,121	[1]	14,940
Cash and cash equivalents at end of period	20,807		21,732
Supplemental disclosure of non-cash activities	'		'
Transfer of fair value of exercised warrants to additional paid-in capital	$496		'

[1]	The condensed consolidated balance sheet as of DecemberÂ 31, 2013 has been derived from the audited financial statements as of that date included in the Companyâ€™s Annual Report on FormÂ 10-K for the year ended DecemberÂ 31, 2013.

Company_Overview

Company Overview	9 Months Ended
Company Overview	Sep. 30, 2014
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, but based upon the favorable results of other predefined analyses of the data, Sunesis plans to commence preparation and submission of a marketing authorization application to the European Medicines Agency (the “EMA”) and to meet with the U.S. Food and Drug Administration to determine a potential regulatory path forward.
	Significant Risks and Uncertainties
	The Company has incurred significant losses and negative cash flows from operations since its inception, and as of September 30, 2014, had cash, cash equivalents and marketable securities totaling $44.7 million and an accumulated deficit of $521.4 million.
	The Company will need to raise substantial additional capital to pursue a regulatory strategy for the potential commercialization of QINPREZOTM (vosaroxin) and to continue the development of QINPREZO and the Company’s other programs. The Company expects to finance its future cash needs primarily through equity issuances, debt arrangements, one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights to QINPREZO and its other development programs, or a combination of the above.
	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_Account

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2014
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, 2013 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, 2013.

	Recent Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), that will supersede most existing revenue recognition guidance under US GAAP. The core principle of the guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Entities can choose to apply the standard using either the full retrospective approach or a modified retrospective approach. Entities electing the full retrospective adoption will apply the standard to each period presented in the financial statements. This means that entities will have to apply the new guidance as if it had been in effect since the inception of all its contracts with customers presented in the financial statements. Entities that elect the modified retrospective approach will apply the guidance retrospectively only to the most current period presented in the financial statements. This means that entities will have to recognize the cumulative effect of initially applying the new standard as an adjustment to the opening balance of retained earnings at the date of initial application. The new revenue standard will be applied to contracts that are in progress at the date of initial application. The standard will be effective for annual and interim periods beginning after December 15, 2016. The Company has yet to evaluate which adoption method it plans to use or the potential effect of the new standard on its consolidated financial statements.
	In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern (“ASU 2014-15”), 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. The standard will be effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company has yet to evaluate the potential effect of the new standard on its consolidated financial statements.
	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 condensed 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 September 30, 2014 and December 31, 2013, the Company held investments denominated in Euros with an aggregate fair value of $0 and $2.6 million, respectively. Any cash, cash equivalent and short-term investment 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 both recorded in other income (expense) 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 September 30, 2014 and December 31, 2013.

Loss_per_Common_Share

Loss per Common Share	9 Months Ended
Loss per Common Share	Sep. 30, 2014
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						Nine months ended
		September 30,						September 30,
		2014			2013			2014			2013
	Numerator:
	Net loss—basic	$	(15,325	)	$	(7,607	)	$	(41,679	)	$	(27,421	)
	Adjustment for change in fair value of warrant liability		—			(722	)		—			—
	Net loss—diluted	$	(15,325	)	$	(8,329	)	$	(41,679	)	$	(27,421	)
	Denominator:
	Weighted-average common shares outstanding—basic		60,549			51,698			59,052			51,639
	Dilutive effect of warrants		—			1,573			—			—
	Weighted-average common shares outstanding—diluted		60,549			53,271			59,052			51,639
	Net loss per common share:
	Basic	$	(0.25	)	$	(0.15	)	$	(0.71	)	$	(0.53	)
	Diluted	$	(0.25	)	$	(0.16	)	$	(0.71	)	$	(0.53	)



	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						Nine months ended
		September 30,						September 30,
		2014			2013			2014			2013
	Warrants to purchase shares of common stock		19,059			6,878			19,059			9,996
	Options to purchase shares of common stock		9,240			7,512			9,240			7,512
	Outstanding securities not included in calculations		28,299			14,390			28,299			17,508

Financial_Instruments

Financial Instruments	9 Months Ended
Financial Instruments	Sep. 30, 2014
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):

	30-Sep-14		Input Level		Amortized				Gross		Gross			Estimated Fair
					Cost				Unrealized		Unrealized			Value
									Gains		Losses
	Money market funds		Level 1		$	9,877			$	—	$	—		$	9,877
	U.S. certificates of deposit		Level 1			2,511				—		—			2,511
	U.S. corporate debt obligations		Level 2			15,513				—		(9	)		15,504
	U.S. commercial paper		Level 2			7,427				—		—			7,427
	Total available-for-sale securities					35,328				—		(9	)		35,319
	Less amounts classified as cash equivalents					(11,407	)			—		—			(11,407	)
	Amounts classified as marketable securities				$	23,921			$	—	$	(9	)	$	23,912

	31-Dec-13		Input Level		Amortized				Gross		Gross			Estimated Fair
					Cost				Unrealized		Unrealized			Value
									Gains		Losses
	Money market funds		Level 1		$	6,282			$	—	$	—		$	6,282
	U.S. corporate debt obligations		Level 2			13,509				—		(4	)		13,505
	U.S. commercial paper		Level 2			8,396				3		—			8,399
	Foreign corporate debt obligations		Level 2			2,571				—		(2	)		2,569
	Total available-for-sale securities					30,758				3		(6	)		30,755
	Less amounts classified as cash equivalents					(6,583	)			—		—			(6,583	)
	Amounts classified as marketable securities				$	24,175			$	3	$	(6	)	$	24,172


	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):

	30-Sep-14		Gross				Estimated Fair
			Unrealized				Value
			Losses
	U.S. corporate debt obligations		$	9			$	15,378
	U.S. commercial paper			—				3,428
			$	9			$	18,806


	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 nine months ended September 30, 2014 or 2013.
	Financial Liabilities
	The following table summarizes the inputs and assumptions and estimated fair value of the Company’s financial liabilities measured 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:

		September 30,				December 31,
		2014				2013
	Inputs and assumptions:
	Fair market value of Company’s common stock	$	7.14			$	4.74
	Exercise price	$	2.52			$	2.52
	Expected term (years)		1				1.8
	Expected volatility		63.9	%			60.8	%
	Risk-free interest rate		0.1	%			0.3	%
	Expected dividend yield		0	%			0	%
	Fair value:
	Estimated fair value per warrant share	$	4.68			$	2.56
	Shares underlying outstanding warrants classified as		2,920				3,099
	liabilities (in thousands)		2,920				3,099
	Total estimated fair value of outstanding warrants	$	13,673			$	7,931
	(in thousands)	$	13,673			$	7,931


	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) in the statements of operations and comprehensive loss, and the fair value of warrant exercises transferred to additional paid-in capital. During the nine months ended September 30, 2014, warrants to purchase 179,427 shares of common stock issued in connection with the 2010 Offering were exercised, resulting in cash proceeds to the Company of $452,000.
	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, 2013		$	7,931
Change in fair value of warrant liability		6,238
Exercise of warrants		(496	)
Balance as of September 30, 2014	$	13,673

Royalty_Agreement

Royalty Agreement	9 Months Ended
Royalty Agreement	Sep. 30, 2014
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.
	Based on the results of the VALOR trial and the Company’s plans to file a marketing authorization application with the European Medicines Agency and to meet with the U.S. Food and Drug Administration to determine a potential regulatory path forward as discussed in Note 1, the Company extended the end date of the estimated performance period through which the balance of deferred revenue will be amortized from June 30, 2015 to September 30, 2016. As a result, the quarterly amortization was adjusted to $0.9 million per quarter, commencing with the quarter ended September 30, 2014, from the previous amortization rate of $2.0 million per quarter.
	Revenue participation right payments will be made to RPI if and when QINPREZO is commercialized, at a rate of 6.75% of net sales of QINPREZO, 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	9 Months Ended
License Agreements	Sep. 30, 2014
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 January 2014, the Company entered into an amended and restated license agreement with Millennium Pharmaceuticals, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited (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 Raf target product rights that were licensed to Millennium under the original license agreement, 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. Millennium is currently conducting a Phase 1 clinical study of an oral investigative drug, MLN2480, which is licensed to them under the Amended Millennium Agreement.

Notes_Payable

Notes Payable	9 Months Ended
Notes Payable	Sep. 30, 2014
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, followed by 32 equal monthly payments of principal and interest from March 1, 2013 to the scheduled maturity date of October 1, 2015. In addition, a final payment equal to $937,500 will be due on October 1, 2015, or such earlier date as specified in the Loan Agreement. The weighted average annual effective interest rate on the notes payable, including the amortization of the debt discounts and accretion of the final payment, is 13.9%.
	Aggregate future minimum payments due under the Loan Agreement as of September 30, 2014 were as follows (in thousands):

	Year ending December 31,
	2014	$	2,644
	2015		8,814
	Total minimum payments		11,458
	Less amount representing interest		(578	)
	Notes payable, gross		10,880
	Unamortized discount on notes payable		(146	)
	Accretion of final payment		838
	Notes payable, balance		11,572
	Less current portion of notes payable		(9,859	)
	Non-current portion of notes payable	$	1,713

Stockholders_Equity

Stockholders' Equity	9 Months Ended
Stockholders' Equity	Sep. 30, 2014
Equity [Abstract]	'
Stockholders' Equity	'
	8. Stockholders’ Equity
	Underwritten Offering
	On March 4, 2014, the Company completed an underwritten offering of 4,650,000 shares of common stock, each with two accompanying warrants to purchase one share of the Company’s common stock at exercise prices of $8.50 (Series A) and $12.00 (Series B) per share, respectively. The purchase price for each share of common stock and two accompanying warrants was $9.25. Gross proceeds from the sale were $43.0 million, and net proceeds were $40.0 million, after deducting the underwriting discount and offering expenses payable by the Company.
	The warrants became exercisable on a gross exercise basis upon unblinding of the VALOR trial, which occurred on October 6, 2014. The Series A warrants will expire on December 4, 2014. The Series B warrants will expire on or before the later of 30 days following any final date assigned by the Food and Drug Administration as the Prescription Drug User Fee Act action date for vosaroxin (the “PDUFA date”) and September 4, 2015, but in no event later than March 4, 2016. The common stock and accompanying warrants have both been classified to stockholders’ equity (deficit) in the Company’s balance sheet.
	Controlled Equity Offerings
	In August 2011, the Company entered into a Controlled Equity OfferingSM sales agreement (the “Sales Agreement”), with Cantor Fitzgerald & Co. (“Cantor”), as agent and/or principal, pursuant to which the Company could issue and sell shares of its common stock having an aggregate gross sales price of up to $20.0 million. In April 2013, the Sales Agreement was amended to provide for an increase of $30.0 million in the aggregate gross sales price under the Sales Agreement. The Company will pay Cantor a commission of 3.0% of the gross proceeds from any common stock sold through the Sales Agreement, as amended.
	During the three months ended September 30, 2014, the Company sold no shares of common stock under the Sales Agreement. During the nine months ended September 30, 2014, the Company sold an aggregate of 1,024,718 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $4.75 per share for gross proceeds of $4.9 million and net proceeds of $4.7 million, after deducting Cantor’s commission. As of September 30, 2014, $16.7 million of common stock remained available to be sold under this facility, subject to certain conditions as specified in the agreement.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
Stock-Based Compensation	Sep. 30, 2014
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				Nine months ended
		September 30,				September 30,
		2014		2013		2014		2013
	Research and development	$	585	$	402	$	1,563	$	1,202
	General and administrative		972		528		2,536		1,486
	Employee stock-based compensation expense		1,557		930		4,099		2,688
	Non-employee stock-based compensation expense		78		103		306		209
	Total stock-based compensation expense	$	1,635	$	1,033	$	4,405	$	2,897

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2014
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, 2013 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, 2013.
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 (“ASU 2014-09”), that will supersede most existing revenue recognition guidance under US GAAP. The core principle of the guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Entities can choose to apply the standard using either the full retrospective approach or a modified retrospective approach. Entities electing the full retrospective adoption will apply the standard to each period presented in the financial statements. This means that entities will have to apply the new guidance as if it had been in effect since the inception of all its contracts with customers presented in the financial statements. Entities that elect the modified retrospective approach will apply the guidance retrospectively only to the most current period presented in the financial statements. This means that entities will have to recognize the cumulative effect of initially applying the new standard as an adjustment to the opening balance of retained earnings at the date of initial application. The new revenue standard will be applied to contracts that are in progress at the date of initial application. The standard will be effective for annual and interim periods beginning after December 15, 2016. The Company has yet to evaluate which adoption method it plans to use or the potential effect of the new standard on its consolidated financial statements.
	In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern (“ASU 2014-15”), 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. The standard will be effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company has yet to evaluate the potential effect of the new standard on its consolidated financial statements.
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 condensed 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 September 30, 2014 and December 31, 2013, the Company held investments denominated in Euros with an aggregate fair value of $0 and $2.6 million, respectively. Any cash, cash equivalent and short-term investment 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 both recorded in other income (expense) 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 September 30, 2014 and December 31, 2013.

Loss_per_Common_Share_Tables

Loss per Common Share (Tables)	9 Months Ended
Loss per Common Share (Tables)	Sep. 30, 2014
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						Nine months ended
		September 30,						September 30,
		2014			2013			2014			2013
	Numerator:
	Net loss—basic	$	(15,325	)	$	(7,607	)	$	(41,679	)	$	(27,421	)
	Adjustment for change in fair value of warrant liability		—			(722	)		—			—
	Net loss—diluted	$	(15,325	)	$	(8,329	)	$	(41,679	)	$	(27,421	)
	Denominator:
	Weighted-average common shares outstanding—basic		60,549			51,698			59,052			51,639
	Dilutive effect of warrants		—			1,573			—			—
	Weighted-average common shares outstanding—diluted		60,549			53,271			59,052			51,639
	Net loss per common share:
	Basic	$	(0.25	)	$	(0.15	)	$	(0.71	)	$	(0.53	)
	Diluted	$	(0.25	)	$	(0.16	)	$	(0.71	)	$	(0.53	)


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						Nine months ended
		September 30,						September 30,
		2014			2013			2014			2013
	Warrants to purchase shares of common stock		19,059			6,878			19,059			9,996
	Options to purchase shares of common stock		9,240			7,512			9,240			7,512
	Outstanding securities not included in calculations		28,299			14,390			28,299			17,508

Financial_Instruments_Tables

Financial Instruments (Tables)	9 Months Ended
Financial Instruments (Tables)	Sep. 30, 2014
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):

	30-Sep-14		Input Level		Amortized				Gross		Gross			Estimated Fair
					Cost				Unrealized		Unrealized			Value
									Gains		Losses
	Money market funds		Level 1		$	9,877			$	—	$	—		$	9,877
	U.S. certificates of deposit		Level 1			2,511				—		—			2,511
	U.S. corporate debt obligations		Level 2			15,513				—		(9	)		15,504
	U.S. commercial paper		Level 2			7,427				—		—			7,427
	Total available-for-sale securities					35,328				—		(9	)		35,319
	Less amounts classified as cash equivalents					(11,407	)			—		—			(11,407	)
	Amounts classified as marketable securities				$	23,921			$	—	$	(9	)	$	23,912

	31-Dec-13		Input Level		Amortized				Gross		Gross			Estimated Fair
					Cost				Unrealized		Unrealized			Value
									Gains		Losses
	Money market funds		Level 1		$	6,282			$	—	$	—		$	6,282
	U.S. corporate debt obligations		Level 2			13,509				—		(4	)		13,505
	U.S. commercial paper		Level 2			8,396				3		—			8,399
	Foreign corporate debt obligations		Level 2			2,571				—		(2	)		2,569
	Total available-for-sale securities					30,758				3		(6	)		30,755
	Less amounts classified as cash equivalents					(6,583	)			—		—			(6,583	)
	Amounts classified as marketable securities				$	24,175			$	3	$	(6	)	$	24,172

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):

	30-Sep-14		Gross				Estimated Fair
			Unrealized				Value
			Losses
	U.S. corporate debt obligations		$	9			$	15,378
	U.S. commercial paper			—				3,428
			$	9			$	18,806

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 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:

		September 30,				December 31,
		2014				2013
	Inputs and assumptions:
	Fair market value of Company’s common stock	$	7.14			$	4.74
	Exercise price	$	2.52			$	2.52
	Expected term (years)		1				1.8
	Expected volatility		63.9	%			60.8	%
	Risk-free interest rate		0.1	%			0.3	%
	Expected dividend yield		0	%			0	%
	Fair value:
	Estimated fair value per warrant share	$	4.68			$	2.56
	Shares underlying outstanding warrants classified as		2,920				3,099
	liabilities (in thousands)		2,920				3,099
	Total estimated fair value of outstanding warrants	$	13,673			$	7,931
	(in thousands)	$	13,673			$	7,931


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, 2013	$	7,931
	Change in fair value of warrant liability		6,238
	Exercise of warrants		(496	)
	Balance as of September 30, 2014	$	13,673

Notes_Payable_Tables

Stock-Based Compensation (Tables)	9 Months Ended
Stock-Based Compensation (Tables)	Sep. 30, 2014
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				Nine months ended
		September 30,				September 30,
		2014		2013		2014		2013
	Research and development	$	585	$	402	$	1,563	$	1,202
	General and administrative		972		528		2,536		1,486
	Employee stock-based compensation expense		1,557		930		4,099		2,688
	Non-employee stock-based compensation expense		78		103		306		209
	Total stock-based compensation expense	$	1,635	$	1,033	$	4,405	$	2,897

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
Stock-Based Compensation (Tables)	Sep. 30, 2014
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				Nine months ended
		September 30,				September 30,
		2014		2013		2014		2013
	Research and development	$	585	$	402	$	1,563	$	1,202
	General and administrative		972		528		2,536		1,486
	Employee stock-based compensation expense		1,557		930		4,099		2,688
	Non-employee stock-based compensation expense		78		103		306		209
	Total stock-based compensation expense	$	1,635	$	1,033	$	4,405	$	2,897

Company_Overview_Additional_In

Company Overview - Additional Information (Detail) (USD $)	9 Months Ended
Company Overview - Additional Information (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'	'
Date of incorporation	10-Feb-98	'
Cash, cash equivalents and marketable securities	$44,700,000	'
Accumulated deficit	$521,374,000	$479,695,000	[1]
Maturity limits period	'24 months	'
Dollars weighted average maturity limit period	'12 months	'

[1]	The condensed consolidated balance sheet as of DecemberÂ 31, 2013 has been derived from the audited financial statements as of that date included in the Companyâ€™s Annual Report on FormÂ 10-K for the year ended DecemberÂ 31, 2013.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
	Segment	Dec. 31, 2013
Accounting Policies [Abstract]	'	'
Number of reportable segment	1	'
Fair value of investments denominated in Euros	$0	$2.60

Loss_per_Common_Share_Computat

Loss per Common Share - Computation of Basic and Diluted Loss per Common Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator:	'	'	'	'
Net loss-basic	($15,325)	($7,607)	($41,679)	($27,421)
Adjustment for change in fair value of warrant liability	'	-722	'	'
Net loss-diluted	($15,325)	($8,329)	($41,679)	($27,421)
Denominator:	'	'	'	'
Weighted-average common shares outstanding-basic	60,549	51,698	59,052	51,639
Dilutive effect of warrants	'	1,573	'	'
Weighted-average common shares outstanding-diluted	60,549	53,271	59,052	51,639
Net loss per common share:	'	'	'	'
Basic	($0.25)	($0.15)	($0.71)	($0.53)
Diluted	($0.25)	($0.16)	($0.71)	($0.53)

Loss_per_Common_Share_Schedule

Loss per Common Share - Schedule of Potential Common Shares Issuable Pursuant to Outstanding Securities Excluded from Computation of Diluted Loss per Common Share (Detail)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]	'	'	'	'
Outstanding securities not included in calculations	28,299	14,390	28,299	17,508
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	19,059	6,878	19,059	9,996
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	9,240	7,512	9,240	7,512

Financial_Instruments_Fair_Val

Financial Instruments - Fair Value of Company's Financial Assets Measured on Recurring Basis (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale securities, Amortized Cost	$35,328	$30,758
Available-for-sale securities, Gross Unrealized Gains	0	3
Available-for-sale securities, Gross Unrealized Losses	-9	-6
Available-for-sale securities, Estimated Fair Value	35,319	30,755
Less amounts classified as cash equivalents, Amortized Cost	-11,407	-6,583
Amounts classified as marketable securities, Amortized Cost	23,921	24,175
Amounts classified as marketable securities, Gross Unrealized Gains	'	3
Amounts classified as marketable securities, Gross Unrealized Losses	-9	-6
Less amounts classified as cash equivalents, Estimated Fair Value	-11,407	-6,583
Amounts classified as marketable securities, Estimated Fair Value	23,912	24,172	[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	9,877	6,282
Available-for-sale securities, Gross Unrealized Gains	0	0
Available-for-sale securities, Estimated Fair Value	9,877	6,282
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	2,511	'
Available-for-sale securities, Gross Unrealized Gains	0	'
Available-for-sale securities, Estimated Fair Value	2,511	'
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	15,513	13,509
Available-for-sale securities, Gross Unrealized Gains	0	0
Available-for-sale securities, Gross Unrealized Losses	-9	-4
Available-for-sale securities, Estimated Fair Value	15,504	13,505
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	7,427	8,396
Available-for-sale securities, Gross Unrealized Gains	0	3
Available-for-sale securities, Estimated Fair Value	7,427	8,399
Level 2 [Member] \| Foreign corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale securities, Amortized Cost	'	2,571
Available-for-sale securities, Gross Unrealized Gains	'	0
Available-for-sale securities, Gross Unrealized Losses	'	-2
Available-for-sale securities, Estimated Fair Value	'	$2,569

[1]	The condensed consolidated balance sheet as of DecemberÂ 31, 2013 has been derived from the audited financial statements as of that date included in the Companyâ€™s Annual Report on FormÂ 10-K for the year ended DecemberÂ 31, 2013.

Financial_Instruments_Summary_

Financial Instruments - Summary of Available-for-Sale Securities in Unrealized Loss Position (Detail) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified	Sep. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Gross Unrealized Losses	$9
Estimated Fair Value	18,806
U.S. corporate debt obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Gross Unrealized Losses	9
Estimated Fair Value	15,378
U.S. commercial paper [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Gross Unrealized Losses	0
Estimated Fair Value	$3,428

Financial_Instruments_Addition

Financial Instruments - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
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	179,427	'
Exercise of warrants for cash	$452,000	'

Financial_Instruments_Summary_1

Financial Instruments - Summary of Assumptions and Estimated Fair Value of Company's Financial Liabilities Measured on Recurring Basis (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Inputs and assumptions:	'	'
Fair market value of Companyâ€™s common stock	$7.14	$4.74
Exercise price	$2.52	$2.52
Expected term (years)	'1 year	'1 year 9 months 18 days
Expected volatility	63.90%	60.80%
Risk-free interest rate	0.10%	0.30%
Expected dividend yield	0.00%	0.00%
Fair value:	'	'
Estimated fair value per warrant share	$4.68	$2.56
Shares underlying outstanding warrants classified as liabilities (in thousands)	2,920	3,099
Total estimated fair value of outstanding warrants (in thousands)	$13,673	$7,931	[1]

[1]	The condensed consolidated balance sheet as of DecemberÂ 31, 2013 has been derived from the audited financial statements as of that date included in the Companyâ€™s Annual Report on FormÂ 10-K for the year ended DecemberÂ 31, 2013.

Financial_Instruments_Summary_2

Financial Instruments - Summary of Changes in Fair Value of Company's Level 3 Financial Liabilities (Detail) (Warrant Liability [Member], USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Warrant Liability [Member]	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'
Beginning Balance	$7,931
Change in fair value of warrant liability	6,238
Exercise of warrants	-496
Ending Balance	$13,673

Royalty_Agreement_Additional_I

Royalty Agreement - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended	1 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2014	Sep. 30, 2012	Sep. 30, 2012
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2014	Royalty Agreement [Member]	Royalty Agreement Terms [Member]
Royalty Agreement [Line Items]	'	'	'	'	'
Acquisition price of revenue participation right	'	'	'	'	$25
Fair value of warrants issued in connection with royalty agreement	'	'	'	3.1	'
Deferred revenue, amortized	$0.90	$2	'	'	'
Revenue participation right payments, rate	6.75%	'	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	'	'

License_Agreements_Additional_

License Agreements - Additional Information (Detail) (USD $)	Sep. 30, 2014	Jan. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	License Agreement Terms [Member]	License Agreement Terms [Member]	Biogen Idec [Member]
	Millennium License Agreements [Member]	Millennium License Agreements [Member]	Development Events [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]	'	'	'
Milestone payment depending on development	'	'	$2.50
Potential pre-commercialization milestone payments payable	'	9.2	'
Potential pre-commercialization payments receivable	$57.50	'	'

Notes_Payable_Additional_Infor

Notes Payable - Additional Information (Detail) (USD $)	9 Months Ended		9 Months Ended				9 Months Ended
	Sep. 30, 2014	Oct. 31, 2011	Sep. 30, 2014	Sep. 30, 2014	Oct. 31, 2011	Oct. 18, 2011	Sep. 30, 2014	Sep. 30, 2012	Sep. 19, 2012
	Tranches		Notes payable [Member]	Tranche one [Member]	Tranche one [Member]	Tranche one [Member]	Tranche two [Member]	Tranche two [Member]	Tranche two [Member]
	Installment
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'	'
Maximum borrowing capacity	'	$25,000,000	'	'	$10,000,000	'	'	$15,000,000	'
Number of tranches for maximum borrowing	2	'	'	'	'	'	'	'	'
Date of Loan and Security Agreement	'	'	'	31-Oct-11	'	'	'	'	'
Line of credit facility remaining amount drawing date	'	'	'	'	'	'	30-Sep-12	'	'
Interest rate	'	'	'	'	'	8.95%	'	'	9.00%
Loan Agreement monthly arrears and interest date	'	'	1-Mar-13	'	'	'	'	'	'
Expiration date	'	'	1-Oct-15	'	'	'	'	'	'
Line of credit facility final payment	$937,500	'	'	'	'	'	'	'	'
Number of installments	32	'	'	'	'	'	'	'	'
Weighted average annual effective interest rate on notes payable, including amortization of debt discounts and accretion	'	'	13.90%	'	'	'	'	'	'

Notes_Payable_Summary_of_Futur

Notes Payable - Summary of Future Minimum Payments Under Loan Agreement (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]	'	'
Notes payable, balance	$11,572	'
Less current portion of notes payable	-9,859	-9,018	[1]
Non-current portion of notes payable	1,713	9,025	[1]
Notes payable [Member]	'	'
Debt Instrument [Line Items]	'	'
2014	2,644	'
2015	8,814	'
Total minimum payments	11,458	'
Less amount representing interest	-578	'
Notes payable, gross	10,880	'
Unamortized discount on notes payable	-146	'
Accretion of final payment	$838	'

[1]	The condensed consolidated balance sheet as of DecemberÂ 31, 2013 has been derived from the audited financial statements as of that date included in the Companyâ€™s Annual Report on FormÂ 10-K for the year ended DecemberÂ 31, 2013.

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)

0 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Millions, except Share data, unless otherwise specified

Mar. 04, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Mar. 04, 2014

Sep. 30, 2014

Aug. 31, 2011

Sep. 30, 2014

Series A warrants [Member]

Series B warrants [Member]

Underwritten Offering [Member]

Controlled Equity Offering Facilities [Member]

Additional Controlled Equity Offerings Facilities [Member]

Series A warrants [Member]

Series B warrants [Member]

Common Stock [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares of common stock issued

4,650,000

Common stock price per share

$9.25

$4.75

Warrants, exercise prices per share

$2.52

$8.50

$12

Proceeds from issuance of common shares and warrants in offering, gross

$43

Proceeds from issuance of common shares and warrants in offering, net

Warrant expiration description

'The Series A warrants will expire on December 4, 2014.

'The Series B warrants will expire on or before the later of 30 days following any final date assigned by the Food and Drug Administration as the Prescription Drug User Fee Act action date for vosaroxin (the â€œPDUFA dateâ€) and September 4, 2015, but in no event later than March 4, 2016.

Issuance of common stock, offering value

Common stock sales agreement, date

'2011-08

Increase in aggregate controlled equity offering agreement as per amendment

Issuance of common stock, commission percentage

3.00%

Common stock sales agreement amended, date

'2013-04

Common stock, shares sold

1,024,718

Proceeds from issuance of common stock through controlled equity offering facilities, gross

4.9

Proceeds from issuance of common stock through controlled equity offering facilities, net

4.7

Issuance of common stock, remaining offering value

$16.70

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Related to Company's Stock-Based Awards (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation, Allocation and Classification in Financial Statements	'	'	'	'
Total stock-based compensation expense	$1,635	$1,033	$4,405	$2,897
Employee stock-based compensation expense [Member]	'	'	'	'
Share-based Compensation, Allocation and Classification in Financial Statements	'	'	'	'
Total stock-based compensation expense	1,557	930	4,099	2,688
Non-employee stock-based compensation expense [Member]	'	'	'	'
Share-based Compensation, Allocation and Classification in Financial Statements	'	'	'	'
Total stock-based compensation expense	78	103	306	209
Research and development [Member]	'	'	'	'
Share-based Compensation, Allocation and Classification in Financial Statements	'	'	'	'
Total stock-based compensation expense	585	402	1,563	1,202
General and administrative [Member]	'	'	'	'
Share-based Compensation, Allocation and Classification in Financial Statements	'	'	'	'
Total stock-based compensation expense	$972	$528	$2,536	$1,486