Aceragen (ACGN) 10-K 12 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 19, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	IDRA
Entity Registrant Name	IDERA PHARMACEUTICALS, INC.
Entity Central Index Key	861838
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		117,836,092
Entity Public Float			$195,698,189

Balance_Sheets

Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$19,971	$26,278
Short-term investments	21,256	3,125
Prepaid expenses and other current assets	1,203	874
Total current assets	42,430	30,277
Long-term investments	7,344	6,189
Property and equipment, net	1,306	90
Restricted cash and other assets	346	311
Total assets	51,426	36,867
Current liabilities:
Accounts payable	2,458	904
Accrued expenses	4,460	3,506
Current portion of note payable	128
Total current liabilities	7,046	4,410
Note payable, net of current portion	742
Other liabilities	236	5
Total liabilities	8,024	4,415
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.01 par value, Authorized - 5,000 shares:
Common stock, $0.001 par value, Authorized - 280,000 shares; Issued and outstanding -94,829 and 66,252 shares at December 31, 2014 and 2013, respectively	95	66
Additional paid-in capital	494,850	434,285
Accumulated deficit	-451,526	-412,884
Accumulated other comprehensive loss	-17	-7
Total stockholders' equity	43,402	32,452
Total liabilities and stockholders' equity	51,426	36,867
Series E Preferred Stock [Member]
Stockholders' equity:
Preferred stock, $0.01 par value		5,528
Total stockholders' equity		5,528
Series D Preferred Stock [Member]
Stockholders' equity:
Preferred stock, $0.01 par value		5,464
Total stockholders' equity		5,464
Series A Preferred Stock [Member]
Stockholders' equity:
Preferred stock, $0.01 par value

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	280,000,000	280,000,000
Common stock, shares issued	94,829,000	66,252,000
Common stock, shares outstanding	94,829,000	66,252,000
Series E Preferred Stock [Member]
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares designated	424,000	424,000
Preferred stock, shares issued	0	424,000
Preferred stock, shares outstanding	0	424,000
Series D Preferred Stock [Member]
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares designated	0	1,124,000
Preferred stock, shares issued	0	1,124,000
Preferred stock, shares outstanding	0	1,124,000
Series A Preferred Stock [Member]
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares designated	1,500,000	1,500,000
Preferred stock, shares issued	1,000	1,000
Preferred stock, shares outstanding	1,000	1,000

Statements_of_Operations_and_C

Statements of Operations and Comprehensive Loss (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Alliance revenue	$73	$47	$51
Operating expenses:
Research and development	27,493	10,475	13,673
General and administrative	11,332	7,741	6,279
Total operating expenses	38,825	18,216	19,952
Loss from operations	-38,752	-18,169	-19,901
Other income (expense):
Decrease in fair value of warrant liability			675
Investment income, net	39	11	9
Foreign currency exchange gain (loss)	71	-68	-23
Net loss	-38,642	-18,226	-19,240
Loss on extinguishment of convertible preferred stock, preferred stock accretion and dividends	519	2,866	3,210
Net loss applicable to common stockholders	-39,161	-21,092	-22,450
Basic and diluted net loss per common share applicable to common stockholders	($0.47)	($0.48)	($0.81)
Shares used in computing basic and diluted net loss per common share applicable to common stockholders	82,827	43,906	27,639
Net loss	-38,642	-18,226	-19,240
Other comprehensive loss:
Increase in unrealized loss and decrease in unrealized gain on available-for-sale securities	-10	-7
Other comprehensive loss	-10	-7
Comprehensive loss	($38,652)	($18,233)	($19,240)

Statements_of_Shareholders_Equ

Statements of Shareholders' Equity (USD $)	Total	Conversion of Series D Preferred Stock to Common [Member]	Conversion of Series E Preferred Stock to Common [Member]	Series E Preferred Stock [Member]	Series E Preferred Stock [Member]	Series D Preferred Stock [Member]	Series D Preferred Stock [Member]	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive (Loss)/Income [Member]
					Conversion of Series E Preferred Stock to Common [Member]		Conversion of Series D Preferred Stock to Common [Member]		Conversion of Series D Preferred Stock to Common [Member]	Conversion of Series E Preferred Stock to Common [Member]		Conversion of Series D Preferred Stock to Common [Member]	Conversion of Series E Preferred Stock to Common [Member]
Beginning balance at Dec. 31, 2011	$12,024,000							$28,000			$387,414,000			($375,418,000)
Beginning balance, shares at Dec. 31, 2011								27,637,000
Exercise of common stock options, warrants and employee stock purchases	4,000										4,000
Exercise of common stock options, warrants and employee stock purchases, shares								5,000
Issuance of common stock for services	1,000										1,000
Issuance of common stock for services, shares								1,000
Non-employee stock option expense	5,000										5,000
Stock-based compensation	2,096,000										2,096,000
Series D redeemable preferred stock beneficial conversion feature	1,238,000										1,238,000
Series D redeemable preferred stock accretion and dividends	-1,908,000										-1,908,000
Transfer of Series D warrant to equity	503,000										503,000
Sale of Series E preferred stock and warrants, net of issuance costs	6,023,000			3,701,000							2,322,000
Sale of Series E preferred stock and warrants, net of issuance costs, shares				424,000
Series E preferred stock beneficial conversion feature				-1,262,000							1,262,000
Series E preferred stock accretion and dividends	-40,000			1,262,000							-1,302,000
Net loss	-19,240,000													-19,240,000
Ending balance at Dec. 31, 2012	706,000			3,701,000				28,000			391,635,000			-394,658,000
Shares of preferred stock outstanding, Ending Balance at Dec. 31, 2012				424,000
Ending balance, shares at Dec. 31, 2012								27,643,000
Sale of common stock and warrants, net of issuance costs	40,102,000							31,000			40,071,000
Sale of common stock and warrants, net of issuance costs, shares								31,227,000
Exercise of common stock options, warrants and employee stock purchases	3,527,000							7,000			3,520,000
Exercise of common stock options, warrants and employee stock purchases, shares								7,346,000
Issuance of common stock for services	26,000										26,000
Issuance of common stock for services, shares								36,000
Non-employee stock option expense	121,000										121,000
Stock-based compensation	1,398,000										1,398,000
Extinguishment of convertible preferred stock & recognition of warrants issued	-5,071,000			-3,701,000							-1,370,000
Extinguishment of convertible preferred stock & recognition of warrants issued, shares				-424,000
Recognition of convertible preferred stock	10,992,000			5,528,000		5,464,000
Recognition of convertible preferred stock, shares				424,000		1,124,000
Series D convertible preferred stock dividends	-756,000										-756,000
Series E convertible preferred stock dividends	-360,000										-360,000
Unrealized loss on marketable securities	-7,000														-7,000
Net loss	-18,226,000													-18,226,000
Ending balance at Dec. 31, 2013	32,452,000			5,528,000		5,464,000		66,000			434,285,000			-412,884,000	-7,000
Shares of preferred stock outstanding, Ending Balance at Dec. 31, 2013				424,000		1,124,000
Ending balance, shares at Dec. 31, 2013	66,252,000							66,252,000
Sale of common stock and warrants, net of issuance costs	37,237,000							8,000			37,229,000
Sale of common stock and warrants, net of issuance costs, shares								7,867,000
Exercise of common stock options, warrants and employee stock purchases	8,456,000							6,000			8,450,000
Exercise of common stock options, warrants and employee stock purchases, shares								5,932,000
Issuance of common stock for services	82,000										82,000
Issuance of common stock for services, shares								27,000
Non-employee stock option expense	24,000										24,000
Stock-based compensation	4,322,000										4,322,000
Series D convertible preferred stock dividends	-66,000										-66,000
Series E convertible preferred stock dividends	-453,000										-453,000
Unrealized loss on marketable securities	-10,000														-10,000
Conversion of preferred stock to common		0	0	-5,528,000	-5,528,000	-5,464,000	-5,464,000		6,000	9,000		5,458,000	5,519,000
Conversion of preferred stock to common, shares					-424,000		-1,124,000		6,266,000	8,485,000
Net loss	-38,642,000													-38,642,000
Ending balance at Dec. 31, 2014	43,402,000							95,000			494,850,000			-451,526,000	-17,000
Shares of preferred stock outstanding, Ending Balance at Dec. 31, 2014				0		0
Ending balance, shares at Dec. 31, 2014	94,829,000							94,829,000
Beginning balance at Nov. 30, 2014
Conversion of preferred stock to common, shares								8,484,840
Ending balance at Dec. 31, 2014								$95,000
Ending balance, shares at Dec. 31, 2014								94,829,000

Statements_of_Cash_Flows

Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows from Operating Activities:
Net loss	($38,642)	($18,226)	($19,240)
Adjustments to reconcile net loss to net cash used in operating activities -
Loss from disposition of assets	1		4
Non-employee stock option expense	24	121	5
Stock-based compensation	4,322	1,398	2,096
Decrease in fair value of warrant liability			-675
Issuance of common stock for services rendered	82	26	1
Amortization of investment premiums	213	9
Depreciation and amortization expense	206	137	251
Changes in operating assets and liabilities -
Prepaid expenses and other current assets	-329	-676	57
Accounts payable, accrued expenses, and other liabilities	2,802	74	-2,415
Net cash used in operating activities	-31,321	-17,137	-19,916
Cash Flows from Investing Activities:
Purchases of available-for-sale securities	-23,623	-9,331
Proceeds from maturity of available-for-sale securities	4,115
Purchases of property and equipment	-1,093	-9
Net cash (used in) provided by investing activities	-20,601	-9,340
Cash Flows from Financing Activities:
Sale of common stock and warrants, net of issuance costs	37,137	40,202
Sale of Series E convertible preferred stock and warrants, net of issuance costs			6,023
Proceeds from issuance of note payable	825
Proceeds from exercise of common stock warrants and options and employee stock purchases	8,456	3,527	4
Dividends paid	-798	-1,066	-583
Payments on capital lease	-5	-4	-3
Net cash provided by financing activities	45,615	42,659	5,441
Net (decrease) increase in cash and cash equivalents	-6,307	16,182	-14,475
Cash and cash equivalents, beginning of year	26,278	10,096	24,571
Cash and cash equivalents, end of year	$19,971	$26,278	$10,096

Organization

Organization	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Organization	1. Organization
	Idera Pharmaceuticals, Inc. (“Idera” or the “Company”) is a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutics for oncology and rare diseases. The Company uses two distinct proprietary drug discovery technology platforms to design and develop drug candidates. The Company developed these platforms based on its scientific expertise and pioneering work with synthetic oligonucleotides as therapeutic agents. Using its Toll-like receptor (“TLR”) targeting technology, the Company designs synthetic oligonucleotide-based drug candidates to act by modulating the activity of specific TLRs. In addition, using its gene silencing oligonucleotide (“GSO”) technology, the Company is developing GSOs to turn off the messenger RNA (“mRNA”) associated with disease causing genes. The Company considers its GSO technology to be a third generation antisense technology that can potentially reduce the immunotoxicity and increase the potency of earlier generation antisense and RNA interference (“RNAi”) technologies.
	Idera is currently conducting a Phase 1/2 clinical trial of IMO-8400 in patients with Waldenström’s macroglobulinemia and Phase 1/2 clinical trial of IMO-8400 in patients with diffuse large B-cell lymphoma (“DLBCL”) who harbor the MYD88 L265P oncogenic mutation. The Company is planning to initiate clinical development of IMO-8400 for the treatment of rare diseases and has selected dermatomyositis and Duchenne muscular dystrophy (“DMD”) as the first non-cancer rare diseases for which it plans to develop IMO-8400. The Company believes it can develop and commercialize therapies on its own in these disease indications, which are characterized by small, well-defined patient populations with serious unmet medical needs.
	The Company is also advancing a second novel synthetic oligonucleotide antagonist of TLR7, TLR8 and TLR9, IMO-9200, as a drug candidate for potential use in selected autoimmune disease indications. The Company is conducting a Phase 1 clinical trial of IMO-9200 in healthy volunteers.
	The Company is also developing its GSOs to specifically address challenges associated with earlier generation antisense and RNAi technologies. Although currently used technologies to silence RNA have demonstrated the ability to inhibit the expression of disease-associated proteins, the Company believes that to reach their full therapeutic potential, gene silencing technologies need to achieve an improved therapeutic index with efficient systemic delivery without using a delivery technology, reduced immunotoxicity and increased potency. The Company is currently undertaking an analysis of oncology and rare disease indications for development of drug candidates from its GSO technology. The Company is planning to conduct disease model studies and begin IND-enabling development programs in each of the first two disease indications selected for further development in its GSO program in the second half of 2015.
	At December 31, 2014, the Company had an accumulated deficit of $451,526,000. The Company expects to incur substantial operating losses in future periods. The Company does not expect to generate significant product revenue, sales-based milestones or royalties until the Company successfully completes development and obtains marketing approval for drug candidates, either alone or in collaborations with third parties, which the Company expects will take a number of years. In order to commercialize its drug candidates, the Company needs to complete clinical development and comply with comprehensive regulatory requirements.
	The Company is subject to a number of risks and uncertainties similar to those of other companies of the same size within the biotechnology industry, such as uncertainty of clinical trial outcomes, uncertainty of additional funding, and history of operating losses.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies
	(a) Basis of Presentation
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	(b) Cash, Cash Equivalents and Investments
	The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at December 31, 2014 and 2013 consisted of cash and money market funds.
	Management determines the appropriate classification of marketable securities at the time of purchase. Investments that the Company does not have the positive intent to hold to maturity are classified as “available-for-sale” and reported at fair market value. Available-for-sale investments are classified as long-term if their contractual maturity is greater than one year at the balance sheet date and the Company does not have the intent to sell them in order to fund current operations. Unrealized gains and losses associated with available-for-sale investments are recorded in “Accumulated other comprehensive income” on the accompanying balance sheets. The amortization of premiums and accretion of discounts, and any realized gains and losses and declines in value judged to be other-than-temporary, and interest and dividends for all available-for-sale securities are included in “Investment income, net” on the accompanying statements of operations. Investments that the Company intends to hold to maturity are classified as “held-to-maturity” investments. The Company had no “held-to-maturity” investments at either December 31, 2014 or 2013. The cost of securities sold is based on the specific identification method.
	The Company had no realized gains or losses from available-for-sale securities in 2014, 2013 or 2012. There were no losses or other-than-temporary declines in value included in “Investment income, net” for any securities for the three years ended December 31, 2014. The Company had no auction rate securities as of December 31, 2014 and 2013.
	(c) Restricted Cash
	As part of the Company’s lease arrangement for its office and laboratory facility, the Company is required to restrict cash held in a certificate of deposit securing a line of credit for the lessor. As of December 31, 2014 and 2013, the restricted cash amounted to $311,000 held in certificates of deposit securing a line of credit for the lessor.
	(d) Depreciation and Amortization
	Depreciation and amortization are computed using the straight-line method based on the estimated useful lives of the related assets. Laboratory and other equipment are depreciated over three to five years. Leasehold improvements are amortized over the remaining lease term or the related useful life, if shorter.
	(e) Revenue Recognition
	For the years ended December 31, 2014, 2013 and 2012, alliance revenue consisted primarily of revenue from the reimbursement by licensees of costs associated with patent maintenance. The Company recognizes the reimbursement revenue during the period in which the related expenses are incurred.
	(f) Financial Instruments
	The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 2(m). The Company is required to disclose the estimated fair values of its financial instruments. The Company’s financial instruments consist of cash, cash equivalents, available-for-sale investments, receivables and a note payable. The estimated fair values of these financial instruments approximate their carrying values as of December 31, 2014 and 2013. As of December 31, 2014, the Company did not have any derivatives, hedging instruments or other similar financial instruments except for the note issued under the Company’s loan and security agreement, which is discussed in Note 5(a), including put and call features which the Company determined are clearly and closely associated with the debt host and do not require bifurcation as a derivative liability, or the fair value of the feature is immaterial. As of December 31, 2013, the Company did not have any derivatives, hedging instruments or other similar financial instruments except for the Series D convertible preferred stock (the “Series D preferred stock”) embedded features discussed in Note 7(a) and the Series E convertible preferred stock (the “Series E preferred stock”) embedded features discussed in Note 8(g).
	(g) Comprehensive Income (Loss)
	Comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive income (loss) for the years ended December 31, 2014, 2013 and 2012 is comprised of reported net income (loss) and any change in net unrealized gains and losses on investments during each year, which is included in “Accumulated other comprehensive income” on the accompanying balance sheets. The Company applies Accounting Standards Update (“ASU”) No. 2011-05, “Comprehensive Income” by presenting the components of net income and other comprehensive income as one continuous statement.
	The following table includes the changes in the accumulated balance of the component of other comprehensive (loss) gain for the years ended December 31, 2014 and 2013:
		Year ended December 31,
	(In thousands)	2014			2013
	Accumulated unrealized loss on available-for-sale securities at beginning of period	$	(7	)	$	—
	Change during the period		(10	)		(7	)
	Accumulated unrealized loss on available-for-sale securities at end of period	$	(17	)	$	(7	)
	There was no accumulated unrealized gain or loss on available-for-sale securities during 2012.
	(h) Net Income (Loss) per Common Share applicable to Common Stockholders
	Basic and diluted net loss per common share applicable to common stockholders is computed using the weighted average number of shares of common stock outstanding during the period. Diluted net loss per common share applicable to common stockholders is the same as basic net loss per common share applicable to common stockholders for each of the three years ended December 31, 2014 as the effects of the Company’s potential common stock equivalents are antidilutive (see Note 12).
	(i) Segment Reporting
	The Company views its operations and manages its business as one operating segment. Accordingly, the Company operates in one segment, which is the business of discovering and developing novel therapeutics that modulate immune responses through TLRs. As a result, the financial information disclosed herein represents all of the material financial information related to the Company’s principal operating segment. For all of the periods presented, all of the Company’s revenues were generated in the United States. As of December 31, 2014 and 2013, all assets were located in the United States.
	(j) Stock-Based Compensation
	The Company recognizes all share-based payments to employees and directors as expense in the statements of operations and comprehensive loss based on their fair values. The Company records compensation expense over an award’s requisite service period, or vesting period, based on the award’s fair value at the date of grant. The Company’s policy is to charge the fair value of stock options as an expense, adjusted for forfeitures, on a straight-line basis over the vesting period, which is generally four years for employees and three years for directors.
	The Company recorded charges of $4,322,000, $1,398,000, and $2,096,000 for the years ended December 31, 2014, 2013 and 2012, respectively, for stock-based compensation expense attributable to share-based payments made to employees and directors. The 2014 charge includes approximately $1,293,000 for the recognition of amortization associated with an employee’s options that were subject to accelerated vesting as a result of a modification. The fair value of each option award is estimated on the date of grant using the Black-Scholes option pricing model. The following assumptions apply to the options to purchase 8,232,424, 5,072,583, and 187,500 shares of common stock granted to employees and directors during the years ended December 31, 2014, 2013 and 2012, respectively:
		2014			2013			2012
	Average risk free interest rate		1.4	%		1.3	%		0.8	%
	Expected dividend yield		—			—			—
	Expected lives (years)		4.4			5			5.6
	Expected volatility		86	%		67	%		62	%
	Weighted average grant date fair value of options granted during the period (per share)	$	2.36		$	0.89		$	0.51
	Weighted average exercise price of options granted during the period (per share)	$	3.69		$	1.55		$	0.92
	The expected lives of the options and the expected volatility are based on historical experience. All options granted during the three years ended December 31, 2014 were granted at exercise prices equal to the fair market value of the common stock on the dates of grant.
	The fair value of options that vested during 2014, 2013 and 2012 amounted to $4,208,000, $1,429,000 and $2,123,000, respectively. The intrinsic value of options exercised amounted to $573,000 and $150,000 during 2014 and 2013, respectively. There were no option exercises in 2012. As of December 31, 2014, there was $18,669,000 of unrecognized compensation cost related to nonvested stock-based compensation arrangements, which the Company expects to recognize over a weighted average period of 3.6 years.
	(k) Research and Development Expenses
	All research and development expenses, including amounts funded by research collaborations, are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including drug development trials and studies, drug manufacturing, laboratory supplies, external research, payroll including stock-based compensation and overhead.
	(l) Concentration of Credit Risk
	Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents and available-for-sale investments. The Company’s credit risk is managed by investing its cash and cash equivalents and marketable securities in highly rated money market instruments, certificates of deposit, corporate bonds, and debt securities. Due to these factors, no significant additional credit risk is believed by management to be inherent in the Company’s assets. As of December 31, 2014, all of the Company’s cash, cash equivalents and investments are held at two financial institutions.
	(m) Fair Value of Assets and Liabilities
	The Company measures fair value at the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date using assumptions that market participants would use in pricing the asset or liability (the “inputs”) into a three-tier fair value hierarchy. This fair value hierarchy gives the highest priority (Level 1) to quoted prices in active markets for identical assets or liabilities and the lowest priority (Level 3) to unobservable inputs in which little or no market data exists, requiring companies to develop their own assumptions. Observable inputs that do not meet the criteria of Level 1, and include quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets and liabilities in markets that are not active, are categorized as Level 2. Level 3 inputs are those that reflect the Company’s estimates about the assumptions market participants would use in pricing the asset or liability, based on the best information available in the circumstances. Valuation techniques for assets and liabilities measured using Level 3 inputs may include unobservable inputs such as projections, estimates and management’s interpretation of current market data. These unobservable Level 3 inputs are only utilized to the extent that observable inputs are not available or cost-effective to obtain. The Company applies ASU No. 2011-04, “Fair Value Measurement (Topic 820),” in its fair value measurements and disclosures.
	The table below presents the assets and liabilities measured and recorded in the financial statements at fair value on a recurring basis at December 31, 2014 and 2013 categorized by the level of inputs used in the valuation of each asset and liability.
	(In thousands)	Total			Quoted Prices			Significant			Significant
					in Active			Other			Unobservable
					Markets			Observable			Inputs
					for Identical			Inputs			(Level 3)
					Assets or			(Level 2)
					Liabilities
					(Level 1)
	December 31, 2014
	Assets
	Money market funds	$	17,156		$	17,156		$	—		$	—
	Other cash equivalents – commercial paper		2,500			—			2,500			—
	Short-term investments – commercial paper		4,494			—			4,494			—
	Short-tem investments – certificate of deposit		500			—			500			—
	Short-term investments – corporate bonds		14,357			—			14,357			—
	Short-term investments – municipal bonds		1,905			—			1,905			—
	Long-term investments		7,344			—			7,344			—
	Total Assets	$	48,256		$	17,156		$	31,100		$	—
Total Liabilities	$	—		$	—		$	—		$	—
December 31, 2013
Assets
Money market funds	$	25,201		$	25,201		$	—		$	—
Short-term investments – commercial paper		1,997			—			1,997			—
Short-term investments– corporate bonds		1,128			—			1,128			—
Long-term investments		6,189			—			6,189			—
Total Assets	$	34,515		$	25,201		$	9,314		$	—
Total Liabilities	$	—		$	—		$	—		$	—
The Level 1 assets consist of money market funds, which are actively traded daily. The Level 2 assets consist of corporate bond, commercial paper, certificate of deposit and municipal bond investments whose fair value may not represent actual transactions of identical securities. The fair value of corporate bonds is generally determined from quoted market prices received from pricing services based upon quoted prices from active markets and/or other significant observable market transactions at fair value. The fair value of commercial paper is generally determined based on the relationship between the investment’s discount rate and the discount rates of the same issuer’s commercial paper available in the market which may not be actively traded daily. The fair value of certificates of deposits approximates carrying value. Since these fair values may not be based upon actual transactions of identical securities, they are classified as Level 2. Since any investments are classified as available-for-sale securities, any unrealized gains or losses are recorded in accumulated other comprehensive income or loss within stockholders’ equity on the balance sheet. The Company did not elect to measure any other financial assets or liabilities at fair value at December 31, 2014 or 2013.
In connection with the sale of its Series D preferred stock in November 2011, the Company issued warrants which contained provisions for anti-dilution protection in the event that the Company issued other equity securities at a price below $1.46 per common share. Because of the potential adjustment to the warrant exercise price that could result from this anti-dilution protection, the warrants did not meet the criteria set forth in ASC 815-40, “Derivatives and Hedging — Contracts in Entity’s own Stock” and the Company recorded the fair value of these warrants as a Level 3 liability at the issuance date using the Black-Scholes option pricing model based, in part, on the Company’s assumptions and significant inputs not observed in the market. The Company revalued the warrants at the end of each quarter using the Black-Scholes option pricing model and recognized the change in the fair value of the warrants in the statements of operations and comprehensive loss as other income (expense).
The sale of shares of Series E preferred stock and Series E warrants in the Company’s November 2012 Series E financing triggered an anti-dilution adjustment under the terms of the Series D warrants, resulting in the exercise price of the Series D warrants being reduced and fixed at the minimum $1.46 per share and the Series D warrants no longer being subject to any anti-dilution adjustments. Since the exercise price of the Series D warrants became fixed, the Series D warrants then met the exception under ASC 815-40 as they were “indexed to the company’s own stock” and met certain criteria for equity classification, thus the Series D warrants were marked to fair value resulting in the recognition of $675,000 of non-operating income during the period ended November 9, 2012 at which time the $503,000 fair value of the warrant liability was transferred to stockholders’ equity. As of December 31, 2012, there was no warrant liability.
(n) New Accounting Pronouncements — Recently Issued
In April 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-08 —Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The amendments in this ASU require that a disposal representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results or a business activity classified as held for sale should be reported as discontinued operations. The amendments also expand the disclosure requirements for discontinued operations and add new disclosure requirements for individually significant components that do not qualify as discontinued operations. This ASU will be effective prospectively for fiscal years beginning on or after December 15, 2014. Early adoption is permitted, but only for disposals that have not been previously reported in financial statements previously issued. The Company does not expect the adoption of this ASU to have a material effect on its financial statements.
In May 2014, the FASB issued ASU No. 2014-09 — Revenue from Contracts with Customers (Topic 606). This ASU requires an entity to recognize revenue from the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In particular, this ASU addresses contracts with more than one performance obligation, as well as the accounting for some costs to obtain or fulfill a contract with a customer, and provides for additional disclosures with respect to revenues and cash flows arising from contracts with customers. This ASU will be effective for fiscal years beginning after December 15, 2016. Early adoption of this ASU is not permitted. The Company is currently evaluating the effect that the adoption of this ASU will have on its financial statements.

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments	3. Investments
	The Company’s available-for-sale investments at fair value consisted of the following at December 31, 2014 and 2013:
		December 31, 2014
		Cost		Gross			Gross		Estimated
				Unrealized			Unrealized		Fair
				(Losses)			Gains		Value
		(In thousands)
	Commercial paper due in one year or less	$	4,493	$	—		$	1	$	4,494
	Certificate of deposit due in one year or less		500		—			—		500
	Corporate bonds due in one year or less		14,364		(7	)		—		14,357
	Municipal bonds due in one year or less		1,906		(1	)		—		1,905
	Total short-term investments		21,263		(8	)		1		21,256
	Corporate bonds due in one year or more		7,354		(10	)		—		7,344
	Total long-term investments		7,354		(10	)		—		7,344
	Total investments	$	28,617	$	(18	)	$	1	$	28,600
		December 31, 2013
		Cost		Gross			Gross		Estimated
				Unrealized			Unrealized		Fair
				(Losses)			Gains		Value
		(In thousands)
	Commercial paper due in one year or less	$	1,997	$	—		$	—	$	1,997
	Corporate bonds due in one year or less		1,128		—			—		1,128
	Total short-term investments		3,125		—			—		3,125
	Corporate bonds due in one year or more		6,196		(7	)		—		6,189
	Total long-term investments		6,196		(7	)		—		6,189
	Total investments	$	9,321	$	(7	)	$	—	$	9,314
	The Company had no realized gains or losses from available-for-sale securities in 2014, 2013 or 2012. There were no losses or other-than-temporary declines in value included in “Investment income, net” for any securities for the three years ended December 31, 2014. The Company had no auction rate securities as of December 31, 2014 and 2013. See Notes 2(f) and 2(m).

Property_and_Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and Equipment
	At December 31, 2014 and 2013, net property and equipment at cost consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Leasehold improvements	$	525	$	525
	Laboratory equipment and other		3,884		2,854
	Total property and equipment, at cost		4,409		3,379
	Less: Accumulated depreciation and amortization		3,103		3,289
	Property and equipment, net	$	1,306	$	90
	Depreciation and amortization expense on property and equipment was approximately $200,000, $137,000 and $251,000 in 2014, 2013 and 2012, respectively.

Note_Payable_and_Accrued_Expen

Note Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Note Payable and Accrued Expenses	5. Note Payable and Accrued Expenses
	(a) Note Payable
	On September 30, 2014, the Company executed a loan and security agreement with Oxford Finance LLC (“Oxford”). Under the agreement, Oxford committed to lend the Company up to an aggregate principal amount of $3,000,000 in one or more advances each of which is to be evidenced by a promissory note. The Company’s obligations to Oxford will be secured by the specific laboratory, manufacturing, office or computer equipment financed under the agreement. Each equipment advance will include interest at a fixed interest rate equal to the greater of 7.5% per annum and 7.27% plus the three-month U.S. Libor Rate per annum, set at the time of funding. The principal amount of each equipment advance will be repaid in 36 monthly installments commencing on the applicable amortization date, which is July 1, 2015 for any equipment advance made on or before June 30, 2015, and is the first monthly payment date for any equipment advance made on or after July 1, 2015. Monthly installments payable prior to July 1, 2015 will consist of accrued interest only and monthly installments payable on or after July 1, 2015 will consist of principal and accrued interest.
	The Company is required to pay a final payment in an amount equal to 5.7% of the aggregate advanced amount under each equipment advance at the time that the final monthly installment is due or such earlier date as specified in the loan and security agreement. The final payments will be accrued as interest expense over the term of each equipment advance using the effective interest method. The weighted average annual effective interest rate on the notes payable based on the amount advanced through December 31, 2014, including accrual of the final payment, is 11.1%. If the Company prepays all or a portion of the principal amount of any equipment advance prior to maturity, it will be required to pay Oxford a prepayment fee of between 1% and 3% of the principal amount of such equipment advance.
	As of December 31, 2014, the Company had received approximately $893,000 in advances under the loan and security agreement and an additional $2,107,000 remained available under the agreement. Aggregate future minimum payments, reflecting payments on outstanding principal plus interest, due under the loan and security agreement as of December 31, 2014, were as follows (in thousands):
	Year ending December 31,
	2015	$	200
	2016		333
	2017		333
	2018		219
	Total minimum payments		1,085
	Less amount representing interest		(192	)
	Notes payable, gross		893
	Unamortized facility fee		(27	)
	Accrual of final payment		4
	Notes payable, balance		870
	Less current portion of notes payable		(128	)
	Non-current portion of notes payable	$	742
	The loan and security agreement includes standard affirmative and restrictive covenants, but does not include any covenants to attain or maintain any financial metrics, and also includes standard events of default, including payment defaults, breaches of covenants following any applicable cure period, a material impairment in the perfection or priority of Oxford’s security interest or in the value of the collateral, a material impairment of the prospect of repayment of the loans and a material adverse change in the business, operations or conditions of the Company. Upon the occurrence of an event of default and following any applicable cure periods, a default interest rate of an additional 5% may be applied to the outstanding loan balances, and Oxford may declare all outstanding obligations immediately due and payable and take such other actions as set forth in the loan and security agreement.
	The Company assessed all terms and features of the note that the Company issued under its loan and security agreement in order to identify any potential embedded features that would require bifurcation. As part of this analysis, the Company assessed the economic characteristics and risks of the note, including put and call features. The Company determined that all features of the note are clearly and closely associated with a debt host and do not require bifurcation as a derivative liability, or the fair value of the feature is immaterial. The Company will continue to reassess the features to determine if they require separate accounting on a quarterly basis.
	(b) Accrued Expenses
	At December 31, 2014 and 2013, accrued expenses consisted of the following:
		December 31,
		2014			2013
		(In thousands)
	Payroll and related costs	$	1,453		$	817
	Clinical and nonclinical trial expenses		2,068			1,277
	Cost of regaining rights to cancer program		251			966
	Professional and consulting fees		530			337
	Other		158			109
		$	4,460		$	3,506

Collaboration_and_License_Agre

Collaboration and License Agreements	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	6. Collaboration and License Agreements
	(a) Collaboration with Abbott Molecular Inc.
	In May 2014, the Company entered into a development and commercialization agreement with Abbott Molecular, Inc. (“Abbott Molecular”) for the development of an in vitro companion diagnostic for use in the Company’s clinical development programs to treat certain genetically defined forms of B-cell lymphoma with IMO-8400, the Company’s lead drug candidate. The agreement provides for the development and subsequent commercialization by Abbott Molecular of a companion diagnostic test utilizing polymerase chain reaction technology to identify with high sensitivity and specificity the presence in tumor biopsy samples of the oncogenic mutation referred to scientifically as MYD88 L265P. Under the agreement, Abbott Molecular is primarily responsible for developing and obtaining regulatory approvals for the companion diagnostic in accordance an agreed development plan and regulatory plan and for making the companion diagnostic test commercially available in accordance with an agreed commercialization plan. Abbott Molecular will retain all proceeds from commercialization of the companion diagnostic test. Subject to the terms of the agreement, the Company will pay Abbott Molecular fees and fund Abbott Molecular’s development of the companion diagnostic test in an approximate aggregate amount of $6.7 million over an approximately five year development period, which includes clinical trial site costs and Abbott Molecular’s costs of preparation and filing fees for regulatory submissions for the companion diagnostic with the U.S. Food and Drug Administration (“FDA”). This amount is subject to increase if Abbott Molecular incurs additional expenses in order to meet unexpected material requirements or obligations not included in the agreement or if the Company is required to conduct additional or different clinical trials which result in Abbott Molecular incurring additional costs. The Company incurred $2.2 million in expenses under the Abbott Molecular agreement through December 31, 2014.
	(b) Collaboration and License Agreement with Merck & Co.
	In December 2006, the Company entered into an exclusive, worldwide license and research collaboration agreement with Merck & Co. to research, develop, and commercialize vaccine products containing the Company’s TLR7, TLR8, and TLR9 agonists in the fields of cancer, infectious diseases, and Alzheimer’s disease. Under the terms of the agreement, the Company granted Merck & Co. exclusive rights to a number of the Company’s TLR7, TLR8, and TLR9 agonists for use in combination with Merck & Co.’s therapeutic and prophylactic vaccines under development in the fields of cancer, infectious diseases, and Alzheimer’s disease. There is no limit under the agreement to the number of vaccines to which Merck & Co. can apply the Company’s agonists within these fields. The Company also agreed with Merck & Co. to engage in a two-year research collaboration to generate novel agonists targeting TLR7 and TLR8 incorporating both Merck & Co. and the Company’s chemistry for use in vaccines in the defined fields. Under the terms of the agreement, Merck & Co. extended the research collaboration for two additional years to December 2010. Under the terms of the agreement:
		•	Merck & Co. paid the Company a $20.0 million upfront license fee;
		•	Merck & Co. purchased $10.0 million of the Company’s common stock at $5.50 per share;
		•	Merck & Co. agreed to fund the research and development collaboration through its term;
		•	Merck & Co. agreed to pay the Company milestone payments as follows:
		•	up to $165.0 million if vaccines containing the Company’s TLR9 agonist compounds are successfully developed and marketed in each of the oncology, infectious disease, and Alzheimer’s disease fields;
		•	up to $260.0 million if vaccines containing the Company’s TLR9 agonist compounds are successfully developed and marketed for follow-on indications in the oncology field and if vaccines containing the Company’s TLR7 or TLR8 agonists are successfully developed and marketed in each of the oncology, infectious disease, and Alzheimer’s disease fields; and
		•	if Merck & Co. develops and commercializes additional vaccines using the Company’s agonists, the Company would be entitled to receive additional milestone payments; and
		•	Merck & Co. agreed to pay the Company mid to upper single-digit royalties on net product sales of vaccines using the Company’s TLR agonist technology that are developed and marketed, with the royalty rates being dependent on disease indication and the TLR agonist employed.
	The Company recognized the $20.0 million upfront payment as revenue over four years, including the initial two-year research term and the two-year extension period that ended in December 2010, which was the Company’s period of continuing involvement under the research collaboration. The Company has recognized a total of $1.0 million of milestone revenue under the license and collaboration agreement, which related to the achievement of a preclinical milestone with one of its TLR9 agonists used as an adjuvant in cancer vaccines.
	In December 2006, in connection with the execution of the license and collaboration agreement, the Company entered into a stock purchase agreement with Merck & Co. Pursuant to such stock purchase agreement, the Company issued and sold to Merck & Co. 1,818,182 shares of the Company’s common stock for a price of $5.50 per share resulting in aggregate gross proceeds of $10.0 million.
	In April 2014, the Company entered into an amendment to the license and research collaboration agreement with Merck & Co. As a result of this amendment, Merck & Co.’s rights under the agreement have been limited to specified TLR7, TLR8, and TLR9 agonists that Merck & Co. selected in January 2012, and the Company regained the rights to pursue its other independently discovered TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in the fields of cancer, infectious diseases and Alzheimer’s disease so that it now has the right to pursue its TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in all fields. Merck & Co.’s obligations under the agreement to pay the Company milestone payments and royalties continue in effect with respect to the specified TLR7, TLR8, and TLR9 agonists. However, in connection with this amendment, the Company agreed that, to the extent that the Company licenses to third parties any TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in the fields of cancer, infectious diseases and Alzheimer’s disease and receives income under such licenses, Merck & Co. may credit against any milestone payments and royalties it owes to the Company an amount equal to 15% of the license income received by the Company under the third-party licenses, up to a maximum of $60.0 million in credits.
	(c) Other License Agreements
	The Company has out-licensed and in-licensed therapies related to antisense technology.
	In 2001, the Company entered into an agreement with Isis Pharmaceuticals, Inc. (“Isis”), under which it granted Isis a license, with the right to sublicense, to its antisense chemistry and delivery patents and patent applications; and it retained the right to use these patents and applications in its own drug discovery and development efforts and in collaborations with third parties. During 2001, Isis paid the Company $15.0 million in cash and issued 857,143 shares of its common stock having an aggregate fair market value on the dates on which title to the shares was received of $17.3 million and is required to pay the Company a low to mid double-digit percentage of specified sublicense income it receives from some types of sublicenses of its patents. As of December 31, 2014, the Company has received $0.3 million in sublicense income from Isis. Also under the agreement, the Company licensed from Isis specified antisense patents and patent applications, principally Isis’ suite of RNase H patents and patent applications. The Company also paid to Isis $0.7 million and issued 1,005,499 shares of common stock having a fair market value of approximately $1.2 million on the date of issuance for this license and is obligated to pay Isis an annual maintenance fee and low single-digit royalties on net sales of antisense products sold that are covered by Isis’s patent rights. The Company has the right to use these patents and patent applications in its drug discovery and development efforts and in some types of third-party collaborations. As of December 31, 2014, the Company has only paid Isis annual maintenance fees and has not paid any royalties. The agreement may be terminated for an uncured material breach by either party. The licenses granted under the Isis agreement terminate upon the last to expire of the patents and patent applications licensed under the agreement. The Company may terminate at any time the sublicense by Isis to it of the patents and patent applications.
	In addition, the Company is a party to other license agreements involving the license of its antisense patents for oligonucleotide chemistry and delivery and for specific gene targets, under which the Company typically is entitled to receive license fees, sublicensing income, research payments, payments upon achievement of developmental milestones, and royalties on product sales. As of December 31, 2014, the Company had received a total of $1.5 million under these agreements.

Series_D_Convertible_Preferred

Series D Convertible Preferred Stock and Warrants	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Series D Convertible Preferred Stock and Warrants	7. Series D Convertible Preferred Stock and Warrants
	The following securities were issued in connection with the Company’s November 4, 2011 financing. As discussed below, on February 6, 2014, all of the shares of Series D preferred stock were converted into 6,266,175 shares of the Company’s common stock.
	(a) Convertible Preferred Stock
	The Series D preferred stock had the rights and preferences set forth in the Certificate of Designations, Preferences and Rights of Series D preferred stock of the Company, as amended (the “Series D Certificate of Designations”), as summarized below.
		•		Dividends — The holders of the Series D preferred stock were entitled to receive dividends payable quarterly in arrears at the rate of 7% per annum. Such dividends were required to be paid in cash through September 30, 2013 and thereafter could have been paid in cash or with shares of common stock or with shares of a to-be-created new series of non-voting preferred stock in the event that payment of such dividends could not be made in shares of its common stock as a result of the application of the beneficial ownership and voting power limitations set forth the Series D Certificate of Designations, as determined by the Company in its sole discretion, except that the Company could not pay any dividends to a holder of Series D preferred stock in shares of common stock to the extent the issuance of such shares would result in the holder of Series D preferred stock and its affiliates beneficially owning more than 19.99% of (i) the common stock outstanding or (ii) the combined voting power of the securities of the Company outstanding immediately after giving effect to the issuance of such shares of common. Dividends payable on the Series D preferred stock amounted to $160,000 at December 31, 2013. There were no dividends payable on the Series D preferred stock at December 31, 2014. Under the original terms of the Series D preferred stock, the 4.6% dividends that the Company originally paid to the Series E preferred stockholders under the terms of the Series E preferred stock were also be paid to the Series D preferred stockholders on an as-converted to common stock basis, which resulted in Series D preferred stockholders being entitled to an additional 2.2% per annum cash dividend payable quarterly in arrears. At the Company’s 2013 annual meeting of stockholders (the “2013 Annual Meeting”), an amendment to the Series D Certificate of Designations to, among other things, modify the terms of the Series D preferred stock requiring payment of dividends to Series D preferred stockholders upon payment of dividends to Series E stockholders was approved by the Company’s stockholders. As a result, the Series E preferred stockholders became entitled to receive dividends payable in cash quarterly in arrears at the rate of 8% per annum and the Series D preferred stockholders ceased to be entitled to corresponding dividends effective July 26, 2013.
		•		Liquidation and Other Events — In the event of a liquidation, dissolution or winding up of the Company (a “Liquidation”), whether voluntary or involuntary, after payment or provision for payment of debts and other liabilities of the Company, the holders of the Series D preferred stock then outstanding were entitled to be paid out of the assets of the Company available for distribution to its stockholders an amount per share of Series D preferred stock equal to the amount that would be payable with respect to such share had all shares of Series D preferred stock been converted into shares of common stock immediately prior to such Liquidation and not any amount greater than that amount in preference to the Company’s common stock. Such amount would have been paid before any cash distribution could be made or any other assets distributed in respect of junior securities to the holders of any junior securities including, without limitation, common stock and Series A preferred stock of the Company. In the event of a sale of the corporation, after payment to the holders of the Series A preferred stock and any other class of capital stock of the Company ranking senior to the Series D preferred stock, the remaining assets of the Company available for distribution to its stockholders will be distributed among the holders of shares of Series E preferred stock, Series D preferred stock and common stock on a pro rata (and as converted to common stock) basis based on the number of shares held by each such holder.
		•		Conversion — Each share of Series D preferred stock was convertible, at the option of the holder thereof, at any time and from time to time, and without the payment of additional consideration by the holder thereof, into such number of fully paid and nonassessable shares of common stock as is determined by dividing the Series D preferred stock original issue price by the Series D preferred stock conversion price in effect at the time of conversion. The Series D preferred stock conversion price was initially equal to $1.63 and the Series D preferred stock issue price was initially equal to the $8.1375 original purchase price of the Series D preferred stock. Accordingly, each share of Series D preferred stock was initially convertible at the option of the holder into five fully paid and nonassessable shares of the common stock. As a result of the Company’s Series E financing in November 2012, the Series D preferred stock conversion price was adjusted to the $1.46 per share minimum resulting in each share of Series D preferred stock becoming convertible at the option of the holder into 5.5736 fully paid and nonassessable shares of the common stock. No holder could convert its shares to the extent such conversion would result in the holder and its affiliates beneficially owning more than 19.99% of the common stock outstanding. The Series D preferred stock conversion price, and the rate at which shares of Series D preferred stock could have been converted into shares of common stock, was subject to adjustment for stock dividends, stock splits and other events, as provided in the Series D Certificate of Designations.
		•		Redemption by Company — After November 4, 2013 and following notice the Company could have redeemed, for cash payment equal to the original Series D preferred stock issue price per share plus any accrued or declared but unpaid dividends thereon, all or a portion of the Series D preferred stock if the closing price of the common stock for 20 or more trading days in a period of 30 consecutive trading days is greater than or equal to 200% of the Series D preferred stock conversion price.
	The effects of the extinguishment of the Series D preferred stock during 2013 are discussed in Note 14.
	On January 10, 2014, the Company notified Pillar Pharmaceuticals I, L.P. (“Pillar I”), an investment partnership managed by one of the Company’s directors and significant stockholders and the holder of all 1,124,260 shares of the Company’s issued and outstanding Series D preferred stock, of its intention to redeem the Series D preferred stock on February 10, 2014 in accordance with the terms of the Series D Certificate of Designations. Following this notice, Pillar I had the right to convert its Series D preferred stock into shares of the Company’s common stock at any time prior to the close of business on February 9, 2014. On February 6, 2014, Pillar I converted such shares into 6,266,175 shares of the Company’s common stock in accordance with the terms of the Series D Certificate of Designations. As a result of the conversion, no shares of the Company’s Series D preferred stock remain outstanding.
	On March 28, 2014, the Company filed a Certificate of Elimination of Number of Shares of Preferred Stock Designated as Series D Convertible Preferred Stock with the State of Delaware Secretary of State which eliminated the designation of the shares of Series D preferred stock.
	At the time of its issuance and prior to being amended, the Series D preferred stock was first assessed under ASC 480, “Distinguishing Liabilities from Equity” and it was determined that it was not within the scope of ASC 480 so the preferred stock was not considered a liability under ASC 480. The preferred stock was then assessed under ASC 815, “Derivatives and Hedging.”
	The Series D preferred stock contained three embedded features: (1) optional redemption by the Company; (2) optional redemption by the holders; and (3) optional conversion by the holders. Each embedded feature met the definition of a derivative. The Company believed that the Series D preferred stock was an equity host for the purposes of assessing the embedded derivatives for potential bifurcation. The Company noted the following regarding these embedded features:
		a.	Optional Redemption by the Company and Optional Redemption by the Holders — the redemption features were assessed under ASC 815-40 to determine if they were eligible for the exemption from derivative accounting. In order to meet the exemption the feature must be “indexed to the company’s own stock” and meet specified criteria for equity classification. Both redemption features met these requirements and were not bifurcated, or accounted for separately from the preferred stock.
		b.	Optional Conversion by the Holder — the optional conversion by the holder feature was determined to be clearly and closely related to the preferred stock host. As such the conversion feature did not require bifurcation under ASC 815.
	The Series D preferred stock was then assessed under ASC 470, “Debt,” to determine if there was a beneficial conversion feature (“BCF”). The BCF compares the carrying value of the preferred stock after the value of any derivatives has been allocated from the proceeds (in this case, the Warrant Liability) to the transaction date value of number of shares that the holder can convert into. The calculation resulted in a BCF of $4,445,000. The BCF was recorded in additional paid-in capital.
	The following is a summary of the changes in the Series D preferred stock during 2012 and 2011 (in thousands):
	Gross proceeds from November 4, 2011 Series D financing (including $351 paid for the warrants)		$	9,500
	Less — allocation of proceeds to:
	Fair value of warrants			(3,152	)
	Beneficial conversion feature			(4,445	)
	Transaction costs			(427	)
	Net proceeds allocated to Series D preferred stock			1,476
	Accretion of beneficial conversion feature			4,445
	Fair value of Series D preferred stock — November 4, 2011		$	5,921
	Fair value of Series D preferred stock — December 31, 2011		$	5,921
	Beneficial conversion feature related to Series E financing			(1,238	)
	Accretion of beneficial conversion feature			1,238
	Fair value of Series D preferred stock — December 31, 2012		$	5,921
	Because the Series D preferred stock was redeemable upon events outside the control of the Company, the Company initially recorded it in temporary equity. The sale of shares and warrants in the Company’s November 2012 Series E financing triggered an anti-dilution adjustment under the terms of the Series D preferred stock, resulting in the conversion price of the Series D preferred stock being reduced and fixed at the minimum $1.46 per share and the Series D preferred stock no longer being subject to any anti-dilution adjustments which resulted in an additional $1,238,000 discount related to the additional BCF. The additional BCF was immediately accreted to preferred dividends in 2012 which resulted in the carrying value of the Series D preferred stock remaining at $5,921,000. The Series D preferred stock was redeemable by the holder for the original $9,149,000 purchase price plus unpaid accrued dividends upon a fundamental change, as described above. The Company has determined that the occurrence of a fundamental change was not probable and did not accrete the difference between the $5,921,000 fair value of the Series D preferred stock and the redemption value of $9,149,000 purchase price plus unpaid accrued dividends. If the occurrence of a fundamental change became probable, the Company would have accreted this $3,228,000 difference at that time.
	The Series D Convertible Preferred Stock and Warrant Purchase Agreement was amended in connection with the Series E financing. The amendments consisted of changes to voting rights limitations and restrictions on the transferability of securities issued in the November 2011 Series D financing. There is no specific guidance on accounting for amendments to preferred stock agreements. However it is generally accepted that such changes should be analyzed to determine if they represent a modification or an extinguishment of the preferred stock. The Company has adopted a qualitative approach to assessing whether amendments are accounted for as modifications or extinguishments. The Company considers the nature of the changes to the preferred stock agreement, including whether the amendments significantly change a substantial contractual term or fundamentally change the nature of the stock; and whether the amendment of the terms would have changed the initial accounting for the stock. If the amendments significantly change a substantial term; fundamentally change the nature of the preferred shares; or change the accounting for the stock, then the change is accounted for as an extinguishment. Otherwise the amendments are accounted for as modifications.
	The Company has considered the nature of these amendments and whether the amendments significantly change any substantial terms that affect the initial accounting for the Series D preferred stock. The Company determined that these Series D amendments related to the November 2012 Series E financing were not to substantial terms of the agreement and did not fundamentally change the nature of the Series D preferred stock. In addition, the Company assessed the original accounting for the Series D preferred stock and determined that the accounting did not change as a result of the amendments. Thus, the changes were considered a modification and not an extinguishment. The Company then considered the appropriate model for accounting for the modification of the Series D preferred stock. The Company considered the debt and the share based payment modification guidance and determined that the share based modification rules included in ASC 718-20-35 were more appropriate. The model under ASC 718-20-35 requires the measurement of the fair value of the Series D preferred stock immediately before and after the modification. The Company determined that the change in fair value resulting from the modification was de minimis, as the Series D amendments related to the Series E financing did not affect substantial terms of the agreement and did not affect the Company’s financial statements.
	(b) Warrants
	The Series D warrants had an initial exercise price of $1.63 per common share (subject to adjustment as provided therein) and may be exercised at the holder’s option at any time on or before November 4, 2016. The sale of shares of Series E preferred stock and Series E warrants in the Company’s November 2012 Series E financing triggered an anti-dilution adjustment under the terms of the Series D warrants, resulting in the conversion price of the Series D warrants being reduced and fixed at the minimum $1.46 per share and the Series D warrants no longer being subject to any anti-dilution adjustments. The Series D warrants provide that the Company shall not effect any exercise of the Series D warrants, and the Series D warrants may not be exercised with respect to any portion of the Series D warrants, to the extent that such exercise would result in the holder and its affiliates beneficially owning more than 19.99% of (i) the number of shares of common stock outstanding or (ii) the combined voting power of the securities of the Company outstanding immediately after giving effect to the issuance of shares of Common Stock issuable upon exercise of the Series D warrants. After November 4, 2013, the Company may redeem the Series D warrants for $0.01 per share of common stock issuable on exercise of the Series D warrants following notice to the holder if the closing price of the common stock for 20 or more trading days in a period of 30 consecutive trading days is greater than or equal to $6.51 (subject to adjustment for stock splits, stock dividends, combinations, recapitalizations, reclassifications, and similar transactions affecting the common stock).
	The Series D warrants were first assessed under ASC 480 and it was determined that they were not within its scope so the warrants were not considered a liability under ASC 480. The Series D warrants were then assessed under ASC 815 and were determined to be derivative instruments since the price protection features do not meet the “indexed to the company’s own stock” exemption requirements in ASC 815-40. The Series D warrants were recorded at fair value as of the transaction date and were being marked to fair value through earnings each quarter. The sale of shares of Series E preferred stock and Series E warrants in the Company’s November 2012 Series E financing triggered an anti-dilution adjustment under the terms of the Series D warrants, resulting in the exercise price of the Series D warrants being reduced and fixed at the minimum $1.46 per share and the Series D warrants no longer being subject to any anti-dilution adjustments. Since the exercise price of the Series D warrants became fixed, the Series D warrants then met the exception under ASC 815-40 as they were “indexed to the company’s own stock” and met certain criteria for equity classification. Accordingly, the Series D warrants were marked to fair value through earnings as of November 9, 2012 and the remaining $503,000 was reclassified to stockholders equity at that time. See Note 2(m).
	The Series D warrants were also amended in connection with the November 2012 Series E financing. The amendments consisted of changes in limitations on the Company’s right to redeem the Series D warrants and the Series D warrant holder’s right to exercise the Series D warrants. There is no specific guidance on accounting for amendments to warrant agreements. However it is generally accepted that such changes should be analyzed to determine if they represent a modification or an extinguishment of the warrant. The Company has adopted a qualitative approach to assessing whether amendments are accounted for as modifications or extinguishments. The Company considers the nature of the changes to the warrant agreement, including whether the amendments significantly change a substantial contractual term or fundamentally change the nature of the warrant; and whether the amendment of the terms would have changed the initial accounting for the Series D warrant. If the amendments significantly change a substantial term; fundamentally change the nature of the Series D warrant; or change the accounting for the Series D warrant, then the change is accounted for as an extinguishment. Otherwise the amendments are accounted for as modifications.
	The Company has considered the nature of these amendments and whether the amendments significantly change any substantial terms that affect the initial accounting for the Series D warrants. The Company determined that these amendments were not to substantial terms of the agreement and did not fundamentally change the nature of the Series D warrants. In addition, the Company assessed the original accounting for the Series D warrants and determined that the accounting did not change as a result of the amendments. Thus, the changes were considered a modification and not an extinguishment.
	The Company then considered the appropriate model for accounting for the modification of the Series D warrants. The Company considered the debt and the share based payment modification guidance and determined that the share based modification rules included in ASC 718-20-35 were more appropriate. The model under ASC 718-20-35 requires the measurement of the fair value of the Series D warrants immediately before and after the modification. The Company determined that the change in fair value resulting from the modification was de minimis, as the amendments did not affect substantial terms of the agreement and did not affect the Company’s financial statements.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity
	(a) Common Stock
	Pursuant to the terms of a unit purchase agreement dated as of May 5, 1998, the Company issued and sold a total of 1,199,684 shares of common stock (the “Put Shares”) at a price of $16.00 per share. Under the terms of the unit purchase agreement, the initial purchasers (the “Put Holders”) of the Put Shares have the right (the “Put Right”) to require the Company to repurchase the Put Shares. The Put Right may not be exercised by any Put Holder unless: (1) the Company liquidates, dissolves or winds up its affairs pursuant to applicable bankruptcy law, whether voluntarily or involuntarily; (2) all of the Company’s indebtedness and obligations, including without limitation the indebtedness under the Company’s then outstanding notes, has been paid in full; and (3) all rights of the holders of any series or class of capital stock ranking prior and senior to the common stock with respect to liquidation, including without limitation the Series A convertible preferred stock, have been satisfied in full. The Company may terminate the Put Right upon written notice to the Put Holders if the closing sales price of its common stock exceeds $32.00 per share for the twenty consecutive trading days prior to the date of notice of termination. Because the Put Right is not transferable, in the event that a Put Holder has transferred Put Shares since May 5, 1998, the Put Right with respect to those shares has terminated. As a consequence of the Put Right, in the event the Company is liquidated, holders of shares of common stock that do not have Put Rights with respect to such shares may receive smaller distributions per share upon the liquidation than if there were no Put Rights outstanding.
	As of December 31, 2014, the Company has repurchased or received documentation of the transfer of 399,950 Put Shares and 35,780 of the Put Shares continued to be held in the name of Put Holders. The Company cannot determine at this time what portion of the Put Rights of the remaining 763,954 Put Shares have terminated.
	(b) Warrants
	The Company has the following warrants outstanding and exercisable for the purchase of common stock at December 31, 2014:
	Expiration Date		Shares			Weighted
						Average Exercise
						Price Per share
	August 5, 2015			334,600		$	3.71
	November 4, 2016			2,810,650			1.46
	November 9, 2017			7,484,840			0.7
	May 7, 2018			24,906,327			0.47
	May 7, 2020			15,816,327			0.01
	September 30, 2020			4,175,975			0.01
	February 10, 2021			2,158,750			0.01
	Total			57,687,469			0.39
	See Note 7(b).
	(c) Stock Options
	Under the Company’s 2013 Stock Incentive Plan (the “2013 Stock Incentive Plan”), the Company may grant options to purchase common stock, stock appreciation rights, restricted stock awards and other forms of stock-based compensation. Stock options generally vest over three to four years, and expire no later than 10 years from the date of grant. A total of 10,224,460 shares of common stock, plus such additional number of shares of common stock (up to 5,720,540) as is equal to the sum of (i) the number of shares of common stock reserved for issuance under the Company’s 2008 Stock Incentive Plan (the “2008 Stock Incentive Plan”) that are available for grant under the 2008 Stock Incentive Plan immediately prior to the date the 2013 Stock Incentive Plan is approved by its stockholders and (ii) the number of shares of common stock subject to awards granted under the 2008 Stock Incentive Plan which awards expire, terminate or are otherwise surrendered, cancelled, or forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right (subject, however, in the case of incentive stock options to any limitations of the Internal Revenue Code of 1986, as amended (the “Code”)), may be issued pursuant to awards granted under the 2013 Stock Incentive Plan subject to reduction in the event that there are any “full-value awards,” as defined in the plan. The maximum number of shares of common stock with respect to which awards may be granted to any participant under the plan is 1,500,000 per calendar year. The compensation committee of the board of directors has the authority to select the employees to whom options are granted and determine the terms of each option, including (i) the number of shares of common stock subject to the option; (ii) when the option becomes exercisable; (iii) the option exercise price, which must be at least 100% of the fair market value of the common stock as of the date of grant; and (iv) the duration of the option, which may not exceed 10 years. Stock options may not be re-priced without shareholder approval. Discretionary awards to non-employee directors are granted and administered by a committee comprised of independent directors. As of December 31, 2014, options to purchase a total of 7,944,549 shares of common stock were outstanding under the 2013 Stock Incentive Plan. As of December 31, 2014, 2,516,500 shares of common stock remain available for grant under the 2013 Stock Incentive Plan.
	The Company is no longer granting stock options or other awards pursuant to the share-based compensation plans that were utilized prior to the approval of the 2013 Stock Incentive Plan. Under these earlier plans, stock options generally vested over three to four years and expired no later than 10 years from the date of grant. As of December 31, 2014, options to purchase a total of 6,406,439 shares of common stock were outstanding under these earlier plans. During 2014, the Company also granted as inducement grants non-statutory stock options to purchase an aggregate of 2,600,000 shares of common stock. The inducement grant awards were made outside of the 2013 Stock Incentive Plan pursuant to the NASDAQ inducement grant exception as a material component of new hires’ employment compensation. All of the inducement grants remained outstanding at December 31, 2014.
	The following table summarizes information related to the outstanding and exercisable options during 2014 (in thousands, except per share amounts and years):
			Stock			Weighted-Average		Weighted-Average		Aggregate
			Options			Exercise Price		Remaining		Intrinsic
								Contractual Life		Value
								(in years)
	Outstanding at December 31, 2013			10,148		$	3.38
	Granted			8,232			3.69
	Exercised			(374	)		2.37
	Forfeited			(825	)		2.18
	Expired			(230	)		6.81
	Outstanding at December 31, 2014			16,951			3.56		8.06	$	23,512
	Exercisable at December 31, 2014			7,393			3.95		6.15		11,950
	Total exercisable or expected to vest			16,320			3.57		8		22,749
	(d) Employee Stock Purchase Plan
	The Company’s 1995 Employee Stock Purchase Plan (the “Stock Purchase Plan”), as amended, provides for the issuance of up to 500,000 shares of common stock to participating employees of the Company or its subsidiaries. Participation is limited to employees that would not own 5% or more of the total combined voting power or value of the stock of the Company after the grant.
	Under the Stock Purchase Plan, on the first day of a designated payroll deduction period, the “Offering Period,” the Company will grant to each eligible employee who has elected to participate in the Stock Purchase Plan an option to purchase shares of common stock as follows: the employee may authorize an amount, a whole percentage from 1% to 10% of such employee’s regular pay, to be deducted by the Company from such pay during the Offering Period. On the last day of the Offering Period, the employee is deemed to have exercised the option, at the option exercise price, to the extent of accumulated payroll deductions. Under the terms of the Stock Purchase Plan, the option price is an amount equal to 85% of the fair market value per share of the common stock on either the first day or the last day of the Offering Period, whichever is lower. In no event may an employee purchase in any one Offering Period a number of shares that is more than 15% of the employee’s annualized base pay divided by 85% of the market value of a share of common stock on the commencement date of the Offering Period. The Compensation Committee may, in its discretion, choose an Offering Period of 12 months or less for each of the Offerings and choose a different Offering Period for each Offering.
	Offering periods are three months in duration and commence on March 1, June 1, September 1, and December 1. In 2014, 2013, and 2012, the Company issued 13,844, 14,716, and 4,746 shares of common stock, respectively, under the Stock Purchase Plan.
	(e) Preferred Stock
	The Restated Certificate of Incorporation of the Company permits its board of directors to issue up to 5,000,000 shares of preferred stock, par value $0.01 per share, in one or more series, to designate the number of shares constituting such series, and fix by resolution, the powers, privileges, preferences and relative, optional or special rights thereof, including liquidation preferences and dividends, and conversion and redemption rights of each such series. As of December 31, 2014, the Company has designated 1,500,000 shares as Series A convertible preferred stock and 424,242 shares of Series E preferred stock (see Note 8(g)). On March 28, 2014, the Company filed a Certificate of Elimination of Number of Shares of Preferred Stock Designated as Series D Convertible Preferred Stock with the State of Delaware Secretary of State which eliminated the designation of the shares of Series D preferred stock.
	(f) Series A Convertible Preferred Stock
	The dividends on the Series A convertible preferred stock are payable semi-annually in arrears at the rate of 1% per annum, at the election of the Company, either in cash or additional duly designated, fully paid and nonassessable shares of Series A preferred stock. The Company paid dividends in stock until 2004 when it elected to pay further dividends in cash. In the event of liquidation, dissolution or winding up of the Company, after payment of debts and other liabilities of the Company, the holders of the Series A convertible preferred stock then outstanding will be entitled to a distribution of $1 per share out of any assets available to shareholders. The Series A preferred stock is non-voting. All remaining shares of Series A preferred stock rank as to payment upon the occurrence of any liquidation event senior to the common stock. Shares of Series A preferred stock are convertible, in whole or in part, at the option of the holder into fully paid and nonassessable shares of common stock at $34.00 per share, subject to adjustment. As of December 31, 2014 and 2013, there were 655 shares of Series A convertible preferred stock outstanding.
	(g) Series E Convertible Preferred Stock
	The Series E convertible preferred stock was issued in connection with the Company’s November 9, 2012 financing discussed in Note 15. As discussed below, in December 2014, all of the shares of Series E preferred stock were converted into 8,484,840 shares of the Company’s common stock.
	On November 9, 2012, the board of directors of the Company designated 424,242 shares as Series E preferred stock, having the rights and preferences set forth in the Certificate of Designations, Preferences and Rights of Series E Preferred Stock (the “Series E Certificate of Designations”). The rights and preferences of Series E preferred stock of the Company set forth in the Series E Certificate of Designations, as amended, are summarized below.
		•		Dividends — The holders of Series E preferred stock were entitled to receive cash dividends payable quarterly in arrears at the Initial Dividend Rate (as defined below) with the first payment date being March 31, 2013. The Company proposed at the 2013 Annual Meeting an amendment to the Series D Certificate of Designations to, among other things, modify the terms of the Series D preferred stock that require payment of dividends to Series D preferred stockholders upon payment of dividends to Series E stockholders. Since the stockholders of the Company approved the amendment to the Series D Certificate of Designations, the dividend rate with respect to the Series E preferred dividends increased from the Initial Dividend Rate to the rate of 8% per annum. The term “Initial Dividend Rate” means 4.6% per annum or such other percentage per annum as may be approved by the Company and by the holders of at least a majority of the then outstanding shares of Series E preferred stock. Dividends payable on the Series E preferred stock amounted to $119,000 at December 31, 2013. There were no dividends payable on the Series E preferred stock at December 31, 2014.
		•		Liquidation and Other Events — In the event of a liquidation, dissolution or winding up of the Company (other than a Sale of the Corporation as defined in the Series E Certificate of Designations) (a “Liquidation”), whether voluntary or involuntary, after payment or provision for payment of debts and other liabilities of the Company, the holders of the Series E preferred stock then outstanding would have been entitled to be paid out of the assets of the Company available for distribution to its stockholders an amount per share of Series E preferred stock equal to the amount that would be payable with respect to such share had all shares of Series E preferred stock been converted into shares of common stock immediately prior to such Liquidation and not any amount greater than that amount in preference to the Company’s common stock. Such amount would have been paid before any cash distribution may be made or any other assets distributed in respect of the holders of common stock, Series A convertible preferred stock, Series D preferred stock or any other class of capital stock of the Company ranking junior to the Series E preferred stock as to liquidation. In the event of a sale of the corporation, after payment to the holders of the Series A preferred stock and any other class of capital stock of the Company ranking senior to the Series E preferred stock, the remaining assets of the Company available for distribution to its stockholders would have been distributed among the holders of shares of Series E preferred stock, Series D preferred stock and common stock on a pro rata (and as converted to common stock) basis based on the number of shares held by each such holder.
		•		Voting — The Series E preferred stock has no voting rights.
		•		Protective Provisions — For so long as at least 84,849 shares of Series E preferred stock, subject to adjustment, remain outstanding, the Company has agreed that it will not, directly or indirectly, (a) amend the Certificate of Incorporation or bylaws of the Company in a manner that adversely and uniquely affects the Series E preferred stock, (b) except as expressly permitted by the Series E Certificate of Designations, purchase or redeem or pay or declare any dividend or make any distribution on, any shares of capital stock of the Company, or (c) recapitalize or reclassify any of the common stock, without in each case the written consent or affirmative vote of the holders of at least 51% of the then outstanding shares of Series E preferred stock.
		•		Conversion — Each share of Series E preferred stock was convertible, at the option of the holder thereof, at any time and from time to time, and without the payment of additional consideration by the holder thereof, into such number of fully paid and nonassessable shares of common stock as is determined by dividing the Series E preferred stock original issue price by the Series E preferred stock conversion price in effect at the time of conversion. The Series E preferred stock conversion price is initially equal to $0.70 and the Series E preferred stock issue price is initially equal to the $14.00 original purchase price of the Series E preferred stock. Accordingly, each share of Series E preferred stock is initially convertible at the option of the holder into 20 fully paid and nonassessable shares of the common stock. No holder could convert its shares to the extent such conversion would result in the holder and its affiliates beneficially owning more than 19.99% of the outstanding common stock or outstanding voting power of the Company (including shares of common stock issuable upon conversion of the Series E preferred stock). The initial Series E preferred stock conversion price, and the rate at which shares of Series E preferred stock may be converted into shares of common stock, was subject to adjustment for stock dividends, stock splits and other similar events, as provided in the Series E Certificate of Designations.
		•		Redemption by Company — After the later of November 9, 2014 and the date that no shares of Series D preferred stock remain outstanding, the Company could have redeemed all or a portion of the Series E preferred stock for a cash payment equal to the original Series E preferred stock issue price per share plus any accrued or declared but unpaid dividends thereon following notice to the holders of the Series E preferred stock if the closing price of the common stock for 20 or more trading days in a period of 30 consecutive trading days is greater than or equal to 400% of the Series E preferred stock conversion price. The Company could not redeem any shares of Series E preferred stock from a holder that could not convert such shares of Series E preferred stock into common stock as a result of the beneficial ownership limitations described above under “Conversion.” In such event, the Company could have redeemed such nonredeemable shares pursuant to alternative redemption provisions set forth in the Series E Certificate of Designations following notice to the holders of the nonredeemable shares, for a cash payment equal to the greater of the 20 consecutive trading day average closing price per share of the common stock ending on the trading day immediately prior to redemption date plus any dividends accrued or declared but unpaid thereon and the Series E conversion price plus any dividends accrued or declared but unpaid thereon.
	The Series E preferred stock was first considered under ASC 480 and it was determined that it was not mandatorily redeemable. The Company identified the following three embedded features within the Series E preferred stock: (1) optional conversion by the holder; (2) optional redemption by the company; and (3) an alternative redemption by the company. The Series E preferred stock was determined to be an equity host. The optional conversion by the holder was assessed to be clearly and closely related to the Series E preferred stock and thus not subject to bifurcation under ASC 815. The optional redemption by the company and the alternative redemption by the company were both indexed to the Company’s own stock and met the criteria for equity classification under ASC 815-40 and thus were not required to be bifurcated. The Series E preferred stock is redeemable only at the Company’s option. In addition, the Series E preferred stock only has preferences in the event of a final liquidation or termination of the Company. In the event of a deemed liquidation, the Series E preferred stock has no preferences and ranks together with the common stockholders. Thus, the Series E preferred stock is not within the scope of ASC 480-10-S99 and will be classified in stockholders’ equity.
	The Series E preferred stock was issued together with warrants to purchase 8,484,840 shares of common stock (the “Series E warrants”). Since the Series E preferred stock and the Series E warrants were classified in stockholders’ equity, the gross proceeds from the financing were allocated between the Series E preferred stock and the Series E warrants based on their relative fair values at the time of the November 9, 2012 Series E financing. The fair value of the Series E warrants was computed using the Black-Scholes option pricing model and was determined to be $2,949,000. The $2,322,000 prorated value of the Series E warrants was recorded as additional paid-in capital.
	The Series E preferred stock was then considered under ASC 470-20 to determine if a BCF existed. As of the transaction date, a BCF of $1,262,000 was computed using the initial stated conversion rate. Since the conversion feature is immediately exercisable, the $1,262,000 BCF was accreted immediately to preferred dividends.
	The following is a summary of the changes in the Series E preferred stock during 2012 (in thousands):
	Gross proceeds from November 9, 2012 Series E financing (including $1,061 paid for the warrants)		$	7,000
	Less — allocation of proceeds to:
	Fair value allocated to warrants			(2,322	)
	Beneficial conversion feature			(1,262	)
	Transaction costs			(977	)
	Net proceeds allocated to Series E preferred stock			2,439
	Accretion of beneficial conversion feature			1,262
	Carrying Value of Series E preferred stock — November 9, 2012		$	3,701
	Carrying Value of Series E preferred stock — December 31, 2012		$	3,701
The effects of the extinguishment of the Series E preferred stock during 2013 are discussed in Note 14.
In December 2014, the holders of Series E preferred stock converted such shares into 8,484,840 shares of common stock in accordance with the terms of the Series E Certificate of Designations. As a result of this conversion, no shares of Series E preferred stock remain outstanding.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies
	(a) Lease Commitments
	During 2014, 2013 and 2012, rent expense, including real estate taxes, was $1,672,000, $1,601,000 and $1,596,000, respectively. As part of the lease, the Company is required to restrict approximately $311,000 of cash for a security deposit as of December 31, 2014. The lease is classified as an operating lease. Future minimum commitments as of December 31, 2014 under the Company’s lease agreement are approximately:
	December 31,	Operating
		Lease
		(In thousands)
	2015	$	1,521
	2016		1,550
	2017		1,046
		$	4,117
	The operating lease was amended on February 21, 2014 to, among other things, extend the expiration date to August 31, 2017 subject to a three-year renewal option exercisable by the Company.
	(b) External Collaborations
	The Company is a party to royalty-bearing license agreements under which it has acquired rights to antisense related patents, patent applications, and technology. Each of these in-licenses automatically terminates upon the expiration of the last to expire patent included in the license. The Company has minimum payments due under one of these agreements of $10,000 in each of 2015 and 2016.
	(c) Contract Obligations
	The Company has employment agreements with its executive officers that include future minimum commitments of approximately $2,246,000 per year.
	(d) Related-Party Transactions
	In November 2011, the Company issued and sold shares of Series D preferred stock and Series D warrants pursuant to a Convertible Preferred Stock and Warrant Purchase Agreement with Pillar I, an investment partnership managed by one of the Company’s directors and significant shareholders, which is described in Note 15. As discussed in Note 7(a), all shares of Series D preferred stock were converted to common stock in February, 2014. In November 2012, the Company issued and sold shares of Series E preferred stock and Series E warrants pursuant to a Convertible Preferred Stock and Warrant Purchase Agreement with Pillar II, an investment partnership managed by two of the Company’s directors and one of its significant shareholders, which is described in Note 15. As discussed in Note 8(g), all shares of Series E preferred stock were converted to common stock in December 2014.
	In connection with the Company’s follow-on underwritten public offering on May 7, 2013, the Company sold 5,000,000 shares of common stock and warrants to purchase 5,000,000 shares of common stock at $0.47 per share for an aggregate purchase price of $2,500,000 to Pillar Pharmaceuticals III, L.P. (“Pillar III”) and an entity affiliated with Pillar III (together with Pillar III, the “Pillar III Entities”), which is described in Note 15. In connection with the Company’s follow-on underwritten public offering on September 30, 2013, the Company sold 1,774,193 shares of common stock for an aggregate purchase price of $2,750,000 to Pillar Pharmaceuticals IV, L.P. (“Pillar IV”) and an entity affiliated with Pillar IV (together with Pillar IV, the “Pillar IV Entities”), which is described in Note 15.
	Youssef El Zein, a member of the Company’s board of directors, is a director and controlling stockholder of Pillar Invest Corporation (“Pillar Invest”), which is the general partner of Pillar I, Pillar II, Pillar III and Pillar IV. Mr. El Zein has voting and investment control over the securities beneficially owned by the Pillar III Entities and the Pillar IV Entities. In addition, Abdul-Wahab Umari, who was also a member of the Company’s board of directors until June 2014, is a managing partner of Pillar Invest.
	The Company paid a director consulting fees of approximately $1,000 in 2012 for services performed in 2011. The Company did not pay any consulting fees to directors in 2014 or 2013. The Company issued common stock in lieu of director board and committee fees of approximately $82,000, $26,000, and $1,000 during 2014, 2013 and 2012, respectively.
	Additional information on related party transactions associated with the April 2013 agreements between the Company and the Pillar Entities (as defined in Note 14) is included in Note 14.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes
	The Tax Reform Act of 1986 contains provisions that limit the amount of net operating loss carryforwards (“NOLs”) and tax credit carryforwards that companies may utilize in any one year in the event of cumulative changes in ownership over a three-year period in excess of 50%. The Company has completed several financings since the effective date of the Tax Reform Act of 1986, which as of December 31, 2014, have resulted in ownership changes in excess of 50% that will significantly limit the Company’s ability to utilize its NOL and tax credit carryforwards. In December, 2014, the Company completed a study which determined that a cumulative three-year ownership change in excess of 50% had occurred in November, 2012. The 2014 federal and state NOLs, tax credit carryforwards and related deferred tax assets shown below have been adjusted to reflect the ownership change limitations that resulted from this study. The corresponding 2013 amounts have not been adjusted. Additional ownership change limitations may result from ownership changes that occur after November 2012.
	As of December 31, 2014, the Company had cumulative NOLs of approximately $79,112,000 and $75,395,000 available to reduce federal and state taxable income. These NOLs expire through 2034. In addition, at December 31, 2014, the Company had cumulative federal and state tax credit carryforwards of $1,680,000 and $749,000, respectively, available to reduce federal and state income taxes which expire through 2034 and 2029, respectively. The federal and state NOLs include approximately $670,000 and $349,000, respectively, of deductions related to the exercise of stock options subsequent to the adoption of ASC 718, “Stock Compensation.” These amounts represent excess tax benefits as defined under ASC 718 and have not been included in the gross deferred tax asset reflected for NOLs.
	As of December 31, 2014 and 2013, the components of the deferred tax assets are approximately as follows:
		2014			2013
		(In thousands)
	Operating loss carryforwards	$	30,632		$	68,500
	Tax credit carryforwards		2,174			9,376
	Other		5,625			5,078
			38,431			82,954
	Valuation allowance		(38,431	)		(82,954	)
		$	—		$	—
	The Company has provided a valuation allowance for its deferred tax asset due to the uncertainty surrounding the ability to realize this asset. The decreases in the operating loss and tax credit carryforward deferred tax assets and the valuation allowance in the current year are primarily attributable to the ownership change limitations discussed above.
	The difference between the 34% U.S. federal corporate tax rate and the Company’s effective tax rate is as follows for the years ended December 31, 2014, 2013 and 2012:
		2014			2013			2012
	Expected federal income tax rate		(34.0	)%		(34.0	)%		(34.0	)%
	Expiring credits and NOLs		—			0.2			116.3
	Change in valuation allowance		(115.3	)		43.1			(76.6	)
	Federal and state credits		(4.0	)		(5.0	)		(0.6	)
	State income taxes, net of federal benefit		(5.1	)		(5.1	)		(5.2	)
	Permanent differences		0.8			0.9			0.1
	Section 382 Limitation		157.5			—			—
	Other		0.1			(0.1	)		—
	Effective tax rate		0	%		0	%		0	%
	The Company applies ASC 740-10, “Accounting for Uncertainty in Income Taxes, an interpretation of ASC 740.” ASC 740-10 clarifies the accounting for uncertainty in income taxes recognized in financial statements and requires the impact of a tax position to be recognized in the financial statements if that position is more likely than not of being sustained by the taxing authority. The Company had no unrecognized tax benefits resulting from uncertain tax positions at December 31, 2014 and 2013.
	The Company has not, as of yet, conducted a study of its research and development credit carryforwards. Such a study might result in an adjustment to the Company’s research and development credit carryforwards, however, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position under ASC 740-10. A full valuation allowance has been provided against the Company’s research and development credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the statements of operations and comprehensive loss if an adjustment was required.
	The Company files income tax returns in the U.S. federal and Massachusetts jurisdictions. The Company is no longer subject to tax examinations for years before 2011, except to the extent that it utilizes NOLs or tax credit carryforwards that originated before 2011. The Company does not believe there will be any material changes in its unrecognized tax positions over the next 12 months. The Company has not incurred any interest or penalties. In the event that the Company is assessed interest or penalties at some point in the future, they will be classified in the statements of operations and comprehensive loss as general and administrative expense.

Employee_Benefit_Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plan	11. Employee Benefit Plan
	The Company has an employee benefit plan under Section 401(k) of the Code. The plan allows employees to make contributions up to a specified percentage of their compensation. Under the plan, the Company matches a portion of the employees’ contributions up to a defined maximum. The Company is currently contributing up to 3% of employee base salary, by matching 50% of the first 6% of annual base salary contributed by each employee. Approximately $139,000, $83,000, and $106,000 of 401(k) benefits were charged to operating expenses during 2014, 2013 and 2012, respectively.

Net_Loss_per_Common_Share_Appl

Net Loss per Common Share Applicable to Common Stockholders	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Loss per Common Share Applicable to Common Stockholders	12. Net Loss per Common Share Applicable to Common Stockholders
	For the years ended December 31, 2014 and 2013, basic and diluted net loss per common share applicable to common stockholders is computed using the weighted average number of shares of common stock outstanding during the period. Diluted net loss per common share applicable to common stockholders is the same as basic net loss per common share applicable to common stockholders as the effects of the Company’s potential common stock equivalents are antidilutive. Total antidilutive securities were 74,640,383 and 85,973,681 at December 31, 2014 and 2013, respectively, and consisted of stock options, preferred stock and warrants.
	For the year ended December 31, 2014, net loss per common share applicable to common stockholders reflects $66,000 and $453,000, respectively, in dividends accrued on shares of Series D preferred stock and Series E preferred stock. For the year ended December 31, 2013, net loss per common share applicable to common stockholders reflects $1,750,000 related to the loss on extinguishment of the Series D preferred stock and the Series E preferred stock that the Company issued in November 2011 and November 2012, respectively, that has been charged to net loss applicable to common stockholders as a preferred stock dividend and $756,000 and $360,000, respectively, in dividends accrued on shares of Series D preferred stock and Series E preferred stock.

Supplemental_Disclosure_of_Cas

Supplemental Disclosure of Cash Flow Information	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosure of Cash Flow Information	13. Supplemental Disclosure of Cash Flow Information
	Supplemental disclosure of cash flow information for the periods presented is as follows:
		Year Ended December 31,
		2014		2013		2012
		(In thousands)
	Supplemental disclosure of cash flow information:
	Cash paid for interest	$	21	$	—	$	—
	Supplemental disclosure of non-cash financing and investing activities:
	Conversion of Series D preferred stock to common stock	$	5,464	$	—	$	—
	Conversion of Series E preferred stock to common stock	$	5,528	$	—	$	—
	Extinguishment of Series D and Series E preferred stock and issuance of related warrants	$	—	$	5,921	$	—
	Accrued 2013 financing transaction costs paid in 2014	$	—	$	100	$	—
	Accretion of Series D redeemable preferred stock beneficial conversion feature	$	—	$	—	$	1,238
	Accretion of Series E preferred stock beneficial conversion feature	$	—	$	—	$	1,262
	Reclassification of Series D warrants from liabilities to stockholders’ equity	$	—	$	—	$	503

April_2013_Pillar_Agreements

April 2013 Pillar Agreements	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
April 2013 Pillar Agreements	14. April 2013 Pillar Agreements
	In April 2013, the Company entered into two agreements (the “Pillar Agreements”) with Pillar I, Pillar II and an entity affiliated with Pillar I and Pillar II (together with Pillar I and Pillar II, the “Pillar Entities”). The agreements, including the Company’s obligations to issue the warrants under the Pillar Agreements, became effective upon the consummation of the follow-on underwritten public offering of the Company’s securities on May 7, 2013. Mr. El Zein, a member of the Company’s board of directors, is a director and controlling stockholder of Pillar Invest, which is the general partner of Pillar I and Pillar II, and is a limited partner of Pillar I and Pillar II. Mr. El Zein has voting and investment control over the securities beneficially owned by the Pillar Entities. In addition, Abdul-Wahab Umari, who was also a member of the Company’s board of directors until June 2014, is a managing partner of Pillar Invest.
	Under the first agreement entered into with Pillar I and Pillar II (the “April 22, 2013 Pillar Agreement”), Pillar I, as the sole holder of the Company’s Series D preferred stock, irrevocably waived and agreed to not exercise the rights, powers, preferences and other terms of the Series D preferred stock under Section 6 of the Series D Certificate of Designations, including without limitation the right to require the Company to purchase all or any portion of the shares of its Series D preferred stock at a price equal to the original Series D preferred stock purchase price per share plus all accrued or declared but unpaid dividends thereon upon the occurrence of specified fundamental changes such as mergers, consolidations, business combinations, stock purchases or similar transactions resulting in a person or group unaffiliated with any holder of Series D preferred stock owning 66.67% or more of the outstanding voting securities of the Company or successor entity (the “Series D Redemption Rights”).
	Under the April 22, 2013 Pillar Agreement, the Company agreed to seek approval and each of Pillar I and Pillar II agreed to vote in favor, of the following proposals at the Company’s 2013 Annual Meeting:
		•		amendments to the Series D Certificate of Designations for the Series D preferred stock to:
		•		modify the dividend provisions of the Series D Certificate of Designations to change the date after which the Company may elect to pay dividends in shares of its common stock from December 31, 2014 to October 1, 2013, and to allow for the payment of such dividends in shares of a to-be-created new series of non-voting preferred stock in the event that payment of such dividends may not be made in shares of its common stock as a result of the application of the beneficial ownership and voting power limitations set forth the Series D Certificate of Designations; and
		•		modify the Series D Certificate of Designations to provide, in the event of a sale of the Company, for the distribution of any assets that remain available for distribution to its stockholders, after payment to the holders of its Series A convertible preferred stock and any other class of its capital stock that ranks senior to its Series D preferred stock, to the holders of the Company’s Series D preferred stock on a pro rata basis with the holders of its common stock, Series E preferred stock and such new series of non-voting preferred stock; and
		•		amendments to the Series E Certificate of Designations to:
		•		modify the dividend provisions of the Series E Certificate of Designations to allow for the payment of dividends in shares of its common stock commencing October 1, 2013; and
		•		allow for the payment of dividends in shares of a to-be-created new series of non-voting preferred stock in the event that payment of such dividends may not be made in shares of its common stock as a result of the application of the beneficial ownership and voting power limitations set forth in the Series E Certificate of Designations.
	Under the second agreement with the Pillar Entities (the “April 30, 2013 Pillar Agreement”), Pillar I irrevocably waived the right of the holders of the Series D preferred stock under Section 2.1 of the Series D Certificate of Designations to receive, in the event of a voluntary or involuntary liquidation, dissolution or winding up of the Company (a “Liquidation”), an amount per share of Series D preferred stock equal to the original issue price of such share of Series D preferred stock plus any dividends accrued or declared but unpaid thereon to the extent such amount is greater than the amount that would have been payable with respect to such share had all shares of Series D preferred stock been converted into shares of the Company’s common stock immediately prior to such Liquidation, and that upon a Liquidation the holders of the Series D preferred stock will receive an amount per share of Series D preferred stock equal to the amount that would be payable with respect to such share had all shares of Series D preferred stock been converted into shares of common stock immediately prior to such Liquidation.
	In addition, under the April 30, 2013 Pillar Agreement, Pillar II and the entity affiliated with Pillar I and Pillar II, as the holders of 100% of the Company’s Series E preferred stock, irrevocably waived the right of the holders of the Series E preferred stock under Section 2.1.1 of the Series E Certificate of Designations to receive, in the event of a Liquidation, an amount per share of Series E preferred stock equal to the original issue price of such share of Series E preferred stock plus any dividends accrued or declared but unpaid thereon to the extent such amount is greater than the amount that would have been payable with respect to such share had all shares of Series E preferred stock been converted into shares of common stock immediately prior to such Liquidation, and that upon a Liquidation the holders of the Series E preferred stock will receive under Section 2.1 of the Series E Certificate of Designations an amount per share of Series E preferred stock equal to the amount that would be payable with respect to such share had all shares of Series E preferred stock been converted into shares of common stock immediately prior to such Liquidation.
	In accordance with the terms of the Pillar Agreements, the Company sought approval from its stockholders of amendments to the Series D Certificate of Designations and Series E Certificate of Designations to effect the changes described above to the dividend and liquidation provisions of the Company’s Series D preferred stock and Series E preferred stock, the redemption rights of the holders of its Series D preferred stock and the rights of the holders of its Series D preferred stock to distributions in the event of a sale of the Company. These matters were approved at the 2013 Annual Meeting that took place on July 26, 2013.
	Under the April 22, 2013 Pillar Agreement, in consideration of the agreements of Pillar I and II under the April 22, 2013 Pillar Agreement and the delivery of the waiver by Pillar I, and for no additional cash consideration, the Company issued to Pillar I warrants, the Pillar I Warrants, to purchase up to 1,000,000 shares of the Company’s common stock at an exercise price of $0.61 per share.
	In addition, under the April 30, 2013 Pillar Agreement, in consideration of the agreements of the Pillar Entities under the April 30, 2013 Pillar Agreement and the delivery of the waivers by the Pillar Entities, and for no additional cash consideration, the Company issued to the Pillar Entities warrants (the “Additional Pillar Warrants,” and together with the Pillar I Warrants, the “Pillar Warrants”), to purchase up to an aggregate of 1,000,000 shares of the Company’s common stock at an exercise price of $0.79 per share.
	The Pillar Warrants became exercisable immediately upon issuance. The Pillar I Warrants will expire if not exercised on or prior to the fifth anniversary from the date of issuance and the Additional Pillar Warrants will expire if not exercised on or prior to June 1, 2014. The Pillar I Warrants provide that, after the second anniversary of the date of issuance, the Company may redeem such Pillar I Warrants for $0.01 per share of common stock issuable on exercise of such Pillar I Warrants following notice to the holder thereof if the closing price of its common stock for 20 or more trading days in a period of 30 consecutive trading days is greater than or equal to $2.80 per share.
	In connection with the Pillar Agreements, the Company filed a registration statement that became effective on July 10, 2013, registering the resale of the shares of common stock issuable upon exercise of the Pillar Warrants. All of the Pillar I Warrants and the Additional Pillar Warrants were exercised during 2014.
	The amendments to the Series D Certificate of Designations and Series E Certificate of Designations did not become effective until the amendments were approved by the Company’s stockholders at the 2013 Annual Meeting, which occurred during the Company’s fiscal quarter that began on July 1, 2013. As discussed in Note 7(a), all shares of Series D preferred stock were converted to common stock in February, 2014. As discussed in Note 8(g), all shares of Series E preferred stock were converted to common stock in December 2014.
	Since Pillar I irrevocably waived and agreed to not exercise the Series D Redemption Rights, the Company reassessed its accounting in May 2013 for the Series D preferred stock, which had been classified as temporary equity in the Company’s condensed balance sheet because the Series D Redemption Rights represented a contingent put feature that was outside the Company’s control. Upon effectiveness of this waiver, the contingent put feature ceased to exist.
	In addition, the Pillar Entities irrevocably waived the liquidation preferences of both the Series D preferred stock and the Series E preferred stock. The Company concluded that these irrevocable waivers of the Series D Redemption Rights and the Series D and Series E liquidation preferences, which became effective on May 7, 2013, represented changes to the fundamental terms of both the Series D preferred stock and the Series E preferred stock. As a result, the Company has accounted for these irrevocable waivers as an extinguishment of the Series D preferred stock and the Series E preferred stock and changed the classification of the Series D preferred stock from temporary equity to permanent equity. The Company compared (1) the sum of the fair values of the Series D preferred stock, the Series E preferred stock and the Pillar Warrants immediately after the effectiveness of the waivers to (2) the sum of the carrying values of the Series D preferred stock and Series E preferred stock immediately prior to the effectiveness of the waivers on May 7, 2013. The Company recorded the excess of the aggregate fair value of the preferred stock plus the Pillar Warrants immediately after the effectiveness of the waivers over the aggregate carrying value of the preferred stock immediately prior to May 7, 2013 as a loss on extinguishment and classified the fair values, immediately after the effectiveness of the waivers, of the Series D preferred stock, the Series E preferred stock and the Pillar Warrants within permanent equity on its balance sheet.
	The effect of this extinguishment accounting on the Company’s financial statements was to (1) remove the $5,921,000 carrying value of the Series D preferred stock immediately prior to the extinguishment from temporary equity; (2) record the $5,464,000 fair value of the Series D preferred stock immediately after the extinguishment in permanent equity (“equity”); (3) remove the $3,701,000 carrying value of the Series E preferred stock immediately prior to the extinguishment from equity; (4) record the $5,528,000 fair value of the Series E preferred stock immediately after the extinguishment in equity; (5) record the $380,000 fair value of the Pillar Warrants in equity; and (6) record a $1,750,000 extinguishment loss to net loss applicable to common stockholders. These accounting entries resulted in a $5,921,000 net increase in stockholders’ equity on its balance sheet.
	The Company determined the fair value of the Series D preferred stock and the Series E preferred stock as of May 7, 2013, the date the above described waivers became effective, based on the Option Pricing Method (“OPM”) which is a market based approach to imply the aggregate equity value of the Company by using the closing price of the Company’s publicly traded common stock as of the May 7, 2013 valuation date. Under the OPM, the fair value of preferred stock and common stock are determined based on the net value of a series of call options representing the present value of the expected future returns to each shareholder class. Essentially, the rights of the common stock are equivalent to a call option on any value of the Company above any cumulative preferred stock liquidation preference. The analysis involves calculating the equity value breakeven points at which the various equity classes would participate, or convert in the case of preferred stock, or exercise in the case of stock options and warrants.
	The Company used the Black-Scholes option pricing model to compute the fair value of the Pillar Warrants as of the May 7, 2013 effective date on which the Pillar Warrants were issued based on the following assumptions and other inputs:
			Pillar I			Additional
			Warrants			Pillar
						Warrants
	Common stock price		$	0.57		$	0.57
	Warrant exercise price		$	0.61		$	0.79
	Term of warrant (years)			5			1.1
	Expected volatility			62	%		67	%
	Average risk free interest rate			0.8	%		0.1	%
	Expected dividend yield			—			—
	Expected percentage of warrants to be exercised			100	%		100	%
	The closing price of the Company’s common stock is readily determinable since it is publicly traded. The warrant exercise prices and the warrant terms are readily determinable from the warrant agreements. The expected volatility is based on the actual stock-price volatility over a period equal to the greater of the term of the warrant or three years. The assumed risk-free interest rate is based on the U.S. Treasury security rate with a term equal to the term of the warrant. The assumed dividend yield of zero is based on the fact that the Company has never paid cash dividends to common stockholders and has no present intention to pay cash dividends to common stockholders. The Company assumed that future financings would dilute the warrant holder’s ownership in the Company such that the 19.99% ownership limitation would not prevent the warrant holder from exercising all of the warrants during the term of the warrants.

Financings

Financings	12 Months Ended
	Dec. 31, 2014
Brokers and Dealers [Abstract]
Financings	15. Financings
	February 10, 2014 Follow-on Underwritten Public Offering
	On February 10, 2014, the Company closed a follow-on underwritten public offering, in which it sold 7,867,438 shares of common stock at a price to the public of $4.00 per share and pre-funded warrants to purchase up to 2,158,750 shares of common stock at a price to the public of $3.99 per share for aggregate gross proceeds of $40.1 million. The pre-funded warrants have an exercise price of $0.01 per share and will expire if not exercised by February 10, 2021. The net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and other offering costs and expenses and excluding the proceeds of the exercise of the warrants, if any, were approximately $37.2 million.
	September 30, 2013 Follow-on Underwritten Public Offering
	On September 30, 2013, the Company closed a follow-on underwritten public offering, in which it sold 13,727,251 shares of common stock at a price to the public of $1.55 per share and pre-funded warrants to purchase up to 4,175,975 shares of common stock at a price to the public of $1.54 per share for aggregate gross proceeds of $27.7 million. The pre-funded warrants have an exercise price of $0.01 per share and will expire if not exercised by September 30, 2020. The net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and offering costs and expenses and excluding the proceeds of the exercise of the warrants, if any, were approximately $25.7 million.
	May 7, 2013 Follow-on Underwritten Public Offering
	On May 7, 2013, the Company closed a follow-on underwritten public offering, in which it sold 17,500,000 shares of common stock, together with matching warrants to purchase up to 17,500,000 shares of common stock, and pre-funded warrants to purchase up to 15,816,327 shares of common stock, together with matching warrants to purchase up to 15,816,327 shares of common stock, for aggregate gross proceeds of $16.5 million as follows:
		Combined		Common		Pre-funded		Matching
		Price to the		Stock		Warrants		Warrants
		Public
		(per share of
		Common
		Stock)
	Common stock and matching warrants sold (shares)	$	0.5		17,500,000		—		17,500,000
	Pre-funded warrants and matching warrants sold (shares)	$	0.49		—		15,816,327		15,816,327
	Total (shares)				17,500,000		15,816,327		33,316,327
	Warrant exercise price (per share)		—		—	$	0.01	$	0.47
	Term of warrant (years)		—		—		7		5
	The net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and offering costs and expenses and excluding the proceeds of the exercise of the warrants, if any, were approximately $14.5 million.
	The warrants and the pre-funded warrants each provide that, after the second anniversary of the date of issuance, the Company may redeem the warrants for $0.01 per share of common stock issuable on exercise of the warrants following 30 days’ prior written notice to the holder if the closing price of the common stock for 20 or more trading days in a period of 30 consecutive trading days is greater than or equal to $2.80.
	Warrant Exercises
	Warrants to purchase 5,543,802 shares of common stock were exercised during 2014. The Company received $7,534,000 in proceeds from the exercise of these warrants.
	Warrants to purchase 7,160,000 shares of common stock were exercised during 2013. The Company received $3,365,000 in proceeds from the exercise of these warrants.
	There were no warrant exercises during 2012.
	Series E Preferred Stock and Warrant Financing
	In November 2012, the Company entered into a Convertible Preferred Stock and Warrant Purchase Agreement (the “Series E Purchase Agreement”) with Pillar II and the other purchaser named therein (together, the “Series E Purchasers”). Pursuant to the Series E Purchase Agreement, the Company issued and sold to the Series E Purchasers, for an aggregate purchase price of approximately $7.0 million, 424,242 shares of its Series E preferred stock and Series E warrants to purchase up to 8,484,840 shares of its common stock. The shares of Series E preferred stock are convertible, subject to limitations, into an aggregate of 8,484,840 shares of common stock at a conversion price of $0.70 per share. The initial exercise price of the Series E warrants is $0.70 per share. The Series E warrants are exercisable immediately, and will expire if not exercised on or prior to November 9, 2017. The Company has agreed to pay to the holders of the Series E preferred stock quarterly dividends payable in cash in arrears at the rate of 4.6% per annum with the first dividend payment being due on March 31, 2013. Under the terms of the Series D preferred stock, any dividends paid to the holders of Series E preferred stock would also be paid to the holders of the Series D preferred stock on an as-converted to common stock basis. The Company agreed that, at the 2013 Annual Meeting, it would, among other things, propose an amendment to the Series D Certificate of Designations to, among other things, modify the terms of the Series D preferred stock that require payment of dividends to Series D preferred stockholders upon payment of dividends to Series E stockholders. Since the stockholders of the Company approved the amendment to the Series D Certificate of Designations, the dividend rate with respect to the Series E preferred dividends increased from the 4.6% to the rate of 8% per annum. The net proceeds to the Company, excluding the proceeds of any exercise of the warrants, were approximately $6.0 million. The Company intends to use these funds for research and clinical development activities, the manufacturing of its drug candidates, working capital and general corporate purposes, including the advancement of the Company’s autoimmune disease program in at least two indications.
	The securities offered by the Company in the private placement were not registered under the Securities Act of 1933, as amended (the “Securities Act”), and cannot be offered or sold in the United States absent registration or an applicable exemption from registration requirements. In January 2013, the Company filed a registration statement with the Securities and Exchange Commission that became effective on January 17, 2013, registering the resale of the shares of common stock issuable upon conversion of the Series E preferred stock and the shares of common stock issuable upon exercise of the Series E warrants issued in the private placement.
	The Company is subject to specified cash penalties if it fails to maintain an effective registration statement with the Securities and Exchange Commission registering the resale of the shares of Common Stock issuable upon conversion of the Series E preferred stock and the shares of Common Stock issuable upon exercise of the Series E warrants. Such penalties are limited to a cumulative maximum penalty equal to 10% of the aggregate purchase price paid to the Company for the Series E preferred stock. The Company is required to maintain the registration statement’s effectiveness until no unregistered shares of Common Stock issued or issuable upon conversion of the Series E preferred stock or upon exercise of the Series E warrants remain outstanding or issuable, as applicable.
	Series D Preferred Stock and Warrant Financing
	In November 2011, the Company entered into a Convertible Preferred Stock and Warrant Purchase Agreement (the “Series D Purchase Agreement”) with Pillar I. Pursuant to the Series D Purchase Agreement, the Company issued and sold to Pillar I, for an aggregate purchase price of $9.5 million, 1,124,260 shares of its Series D preferred stock initially convertible into 5,621,300 shares of its common stock, and Series D warrants to purchase 2,810,650 shares of its common stock. Each share of Series D preferred stock was initially convertible, subject to limitations, at a conversion price of $1.63 per share. The initial exercise price of the Series D warrants was $1.63 per share.
	The sale of shares of Series E preferred stock and Series E warrants in the Company’s November 2012 Series E financing triggered anti-dilution adjustments under the terms of the Series D preferred stock and the Series D warrants. The anti-dilution adjustment under the Series D preferred stock resulted in the conversion price of the Series D preferred stock being reduced and fixed at $1.46 per share, and such shares no longer being subject to any anti-dilution adjustments. Each share of Series D preferred stock became convertible into 5.5736 shares of the Company’s common stock and, as a result, the 1,124,260 shares of Series D preferred stock became convertible, subject to limitations, into 6,266,175 shares of the Company’s common stock. The anti-dilution adjustment under the Series D warrants resulted in the exercise price of the Series D warrants being reduced and fixed at the minimum $1.46 per share and the Series D warrants no longer being subject to any anti-dilution adjustments.
	The net proceeds to the Company, excluding the proceeds of any exercise of the Series D warrants, were approximately $9.1 million which was allocated as described in Note 7(a). The Company used these funds for research and product development activities, including costs of conducting preclinical studies and clinical trials, and for general corporate purposes.
	The securities offered by the Company in the private placement were not registered under the Securities Act and cannot be offered or sold in the United States absent registration or an applicable exemption from registration requirements. In December 2011, the Company filed a registration statement with the Securities and Exchange Commission that became effective on December 21, 2011, registering the resale of the shares of common stock issuable upon conversion of the Series D preferred stock and the shares of common stock issuable upon exercise of the warrants issued in the private placement. In February 2013, the Company filed a registration statement with the Securities and Exchange Commission that became effective on February 8, 2013, covering the resale of additional shares of common stock issuable upon conversion of the Series D preferred stock.
	The Company is subject to specified cash penalties if it fails to maintain an effective registration statement with the Securities and Exchange Commission registering the resale of the shares of common stock issued upon conversion of the Series D preferred stock and the shares of common stock issuable upon exercise of the Series D warrants. Such penalties are limited to a cumulative maximum penalty equal to 10% of the aggregate purchase price paid to the Company by Pillar I for the Series D preferred stock. The Company is required to maintain the registration statement’s effectiveness until no unregistered shares of common stock issued or issuable upon conversion of the Series D preferred stock or upon exercise of the Series D warrants remain outstanding or issuable, as applicable.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Event
	February 19, 2015 Follow-on Underwritten Public Offering
	On February 19, 2015, the Company closed a follow-on underwritten public offering, in which it sold 23,000,000 shares of common stock at a price to the public of $3.75 per share for aggregate gross proceeds of $86.3 million. The estimated net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and other offering costs and expenses were approximately $80.6 million. Investment funds affiliated with Baker Bros. Advisors LP and two members of the Company’s board of directors purchased 5,333,333 shares in this offering at $3.75 per share.
	As of February 19, 2015, Baker Bros. Advisors LP and certain of its affiliated funds (which include the Selling Stockholders) (collectively, “Baker Brothers”), held 6,965,432 shares of the Company’s common stock, warrants to purchase up to 20,316,327 shares of the Company’s common stock at an exercise price of $0.47 per share and pre-funded warrants to purchase up to 22,151,052 shares of the Company’s common stock at an exercise price of $0.01 per share.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	(a) Basis of Presentation
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Cash, Cash Equivalents and Investments	(b) Cash, Cash Equivalents and Investments
	The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at December 31, 2014 and 2013 consisted of cash and money market funds.
	Management determines the appropriate classification of marketable securities at the time of purchase. Investments that the Company does not have the positive intent to hold to maturity are classified as “available-for-sale” and reported at fair market value. Available-for-sale investments are classified as long-term if their contractual maturity is greater than one year at the balance sheet date and the Company does not have the intent to sell them in order to fund current operations. Unrealized gains and losses associated with available-for-sale investments are recorded in “Accumulated other comprehensive income” on the accompanying balance sheets. The amortization of premiums and accretion of discounts, and any realized gains and losses and declines in value judged to be other-than-temporary, and interest and dividends for all available-for-sale securities are included in “Investment income, net” on the accompanying statements of operations. Investments that the Company intends to hold to maturity are classified as “held-to-maturity” investments. The Company had no “held-to-maturity” investments at either December 31, 2014 or 2013. The cost of securities sold is based on the specific identification method.
	The Company had no realized gains or losses from available-for-sale securities in 2014, 2013 or 2012. There were no losses or other-than-temporary declines in value included in “Investment income, net” for any securities for the three years ended December 31, 2014. The Company had no auction rate securities as of December 31, 2014 and 2013.
Restricted Cash	(c) Restricted Cash
	As part of the Company’s lease arrangement for its office and laboratory facility, the Company is required to restrict cash held in a certificate of deposit securing a line of credit for the lessor. As of December 31, 2014 and 2013, the restricted cash amounted to $311,000 held in certificates of deposit securing a line of credit for the lessor.
Depreciation and Amortization	(d) Depreciation and Amortization
	Depreciation and amortization are computed using the straight-line method based on the estimated useful lives of the related assets. Laboratory and other equipment are depreciated over three to five years. Leasehold improvements are amortized over the remaining lease term or the related useful life, if shorter.
Revenue Recognition	(e) Revenue Recognition
	For the years ended December 31, 2014, 2013 and 2012, alliance revenue consisted primarily of revenue from the reimbursement by licensees of costs associated with patent maintenance. The Company recognizes the reimbursement revenue during the period in which the related expenses are incurred.
Financial Instruments	(f) Financial Instruments
	The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 2(m). The Company is required to disclose the estimated fair values of its financial instruments. The Company’s financial instruments consist of cash, cash equivalents, available-for-sale investments, receivables and a note payable. The estimated fair values of these financial instruments approximate their carrying values as of December 31, 2014 and 2013. As of December 31, 2014, the Company did not have any derivatives, hedging instruments or other similar financial instruments except for the note issued under the Company’s loan and security agreement, which is discussed in Note 5(a), including put and call features which the Company determined are clearly and closely associated with the debt host and do not require bifurcation as a derivative liability, or the fair value of the feature is immaterial. As of December 31, 2013, the Company did not have any derivatives, hedging instruments or other similar financial instruments except for the Series D convertible preferred stock (the “Series D preferred stock”) embedded features discussed in Note 7(a) and the Series E convertible preferred stock (the “Series E preferred stock”) embedded features discussed in Note 8(g).
Comprehensive Income (Loss)	(g) Comprehensive Income (Loss)
	Comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive income (loss) for the years ended December 31, 2014, 2013 and 2012 is comprised of reported net income (loss) and any change in net unrealized gains and losses on investments during each year, which is included in “Accumulated other comprehensive income” on the accompanying balance sheets. The Company applies Accounting Standards Update (“ASU”) No. 2011-05, “Comprehensive Income” by presenting the components of net income and other comprehensive income as one continuous statement.
	The following table includes the changes in the accumulated balance of the component of other comprehensive (loss) gain for the years ended December 31, 2014 and 2013:
		Year ended December 31,
	(In thousands)	2014			2013
	Accumulated unrealized loss on available-for-sale securities at beginning of period	$	(7	)	$	—
	Change during the period		(10	)		(7	)
	Accumulated unrealized loss on available-for-sale securities at end of period	$	(17	)	$	(7	)
	There was no accumulated unrealized gain or loss on available-for-sale securities during 2012.
Net Income (Loss) per Common Share Applicable to Common Stockholders	(h) Net Income (Loss) per Common Share applicable to Common Stockholders
	Basic and diluted net loss per common share applicable to common stockholders is computed using the weighted average number of shares of common stock outstanding during the period. Diluted net loss per common share applicable to common stockholders is the same as basic net loss per common share applicable to common stockholders for each of the three years ended December 31, 2014 as the effects of the Company’s potential common stock equivalents are antidilutive (see Note 12).
Segment Reporting	(i) Segment Reporting
	The Company views its operations and manages its business as one operating segment. Accordingly, the Company operates in one segment, which is the business of discovering and developing novel therapeutics that modulate immune responses through TLRs. As a result, the financial information disclosed herein represents all of the material financial information related to the Company’s principal operating segment. For all of the periods presented, all of the Company’s revenues were generated in the United States. As of December 31, 2014 and 2013, all assets were located in the United States.
Stock-Based Compensation	(j) Stock-Based Compensation
	The Company recognizes all share-based payments to employees and directors as expense in the statements of operations and comprehensive loss based on their fair values. The Company records compensation expense over an award’s requisite service period, or vesting period, based on the award’s fair value at the date of grant. The Company’s policy is to charge the fair value of stock options as an expense, adjusted for forfeitures, on a straight-line basis over the vesting period, which is generally four years for employees and three years for directors.
	The Company recorded charges of $4,322,000, $1,398,000, and $2,096,000 for the years ended December 31, 2014, 2013 and 2012, respectively, for stock-based compensation expense attributable to share-based payments made to employees and directors. The 2014 charge includes approximately $1,293,000 for the recognition of amortization associated with an employee’s options that were subject to accelerated vesting as a result of a modification. The fair value of each option award is estimated on the date of grant using the Black-Scholes option pricing model. The following assumptions apply to the options to purchase 8,232,424, 5,072,583, and 187,500 shares of common stock granted to employees and directors during the years ended December 31, 2014, 2013 and 2012, respectively:
		2014			2013			2012
	Average risk free interest rate		1.4	%		1.3	%		0.8	%
	Expected dividend yield		—			—			—
	Expected lives (years)		4.4			5			5.6
	Expected volatility		86	%		67	%		62	%
	Weighted average grant date fair value of options granted during the period (per share)	$	2.36		$	0.89		$	0.51
	Weighted average exercise price of options granted during the period (per share)	$	3.69		$	1.55		$	0.92
	The expected lives of the options and the expected volatility are based on historical experience. All options granted during the three years ended December 31, 2014 were granted at exercise prices equal to the fair market value of the common stock on the dates of grant.
	The fair value of options that vested during 2014, 2013 and 2012 amounted to $4,208,000, $1,429,000 and $2,123,000, respectively. The intrinsic value of options exercised amounted to $573,000 and $150,000 during 2014 and 2013, respectively. There were no option exercises in 2012. As of December 31, 2014, there was $18,669,000 of unrecognized compensation cost related to nonvested stock-based compensation arrangements, which the Company expects to recognize over a weighted average period of 3.6 years.
Research and Development Expenses	(k) Research and Development Expenses
	All research and development expenses, including amounts funded by research collaborations, are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including drug development trials and studies, drug manufacturing, laboratory supplies, external research, payroll including stock-based compensation and overhead.
Concentration of Credit Risk	(l) Concentration of Credit Risk
	Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents and available-for-sale investments. The Company’s credit risk is managed by investing its cash and cash equivalents and marketable securities in highly rated money market instruments, certificates of deposit, corporate bonds, and debt securities. Due to these factors, no significant additional credit risk is believed by management to be inherent in the Company’s assets. As of December 31, 2014, all of the Company’s cash, cash equivalents and investments are held at two financial institutions.
Fair Value of Assets and Liabilities	(m) Fair Value of Assets and Liabilities
	The Company measures fair value at the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date using assumptions that market participants would use in pricing the asset or liability (the “inputs”) into a three-tier fair value hierarchy. This fair value hierarchy gives the highest priority (Level 1) to quoted prices in active markets for identical assets or liabilities and the lowest priority (Level 3) to unobservable inputs in which little or no market data exists, requiring companies to develop their own assumptions. Observable inputs that do not meet the criteria of Level 1, and include quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets and liabilities in markets that are not active, are categorized as Level 2. Level 3 inputs are those that reflect the Company’s estimates about the assumptions market participants would use in pricing the asset or liability, based on the best information available in the circumstances. Valuation techniques for assets and liabilities measured using Level 3 inputs may include unobservable inputs such as projections, estimates and management’s interpretation of current market data. These unobservable Level 3 inputs are only utilized to the extent that observable inputs are not available or cost-effective to obtain. The Company applies ASU No. 2011-04, “Fair Value Measurement (Topic 820),” in its fair value measurements and disclosures.
	The table below presents the assets and liabilities measured and recorded in the financial statements at fair value on a recurring basis at December 31, 2014 and 2013 categorized by the level of inputs used in the valuation of each asset and liability.
	(In thousands)	Total			Quoted Prices			Significant			Significant
					in Active			Other			Unobservable
					Markets			Observable			Inputs
					for Identical			Inputs			(Level 3)
					Assets or			(Level 2)
					Liabilities
					(Level 1)
	December 31, 2014
	Assets
	Money market funds	$	17,156		$	17,156		$	—		$	—
	Other cash equivalents – commercial paper		2,500			—			2,500			—
	Short-term investments – commercial paper		4,494			—			4,494			—
	Short-tem investments – certificate of deposit		500			—			500			—
	Short-term investments – corporate bonds		14,357			—			14,357			—
	Short-term investments – municipal bonds		1,905			—			1,905			—
	Long-term investments		7,344			—			7,344			—
	Total Assets	$	48,256		$	17,156		$	31,100		$	—
	Total Liabilities	$	—		$	—		$	—		$	—
	December 31, 2013
	Assets
	Money market funds	$	25,201		$	25,201		$	—		$	—
	Short-term investments – commercial paper		1,997			—			1,997			—
	Short-term investments– corporate bonds		1,128			—			1,128			—
	Long-term investments		6,189			—			6,189			—
	Total Assets	$	34,515		$	25,201		$	9,314		$	—
	Total Liabilities	$	—		$	—		$	—		$	—
	The Level 1 assets consist of money market funds, which are actively traded daily. The Level 2 assets consist of corporate bond, commercial paper, certificate of deposit and municipal bond investments whose fair value may not represent actual transactions of identical securities. The fair value of corporate bonds is generally determined from quoted market prices received from pricing services based upon quoted prices from active markets and/or other significant observable market transactions at fair value. The fair value of commercial paper is generally determined based on the relationship between the investment’s discount rate and the discount rates of the same issuer’s commercial paper available in the market which may not be actively traded daily. The fair value of certificates of deposits approximates carrying value. Since these fair values may not be based upon actual transactions of identical securities, they are classified as Level 2. Since any investments are classified as available-for-sale securities, any unrealized gains or losses are recorded in accumulated other comprehensive income or loss within stockholders’ equity on the balance sheet. The Company did not elect to measure any other financial assets or liabilities at fair value at December 31, 2014 or 2013.
	In connection with the sale of its Series D preferred stock in November 2011, the Company issued warrants which contained provisions for anti-dilution protection in the event that the Company issued other equity securities at a price below $1.46 per common share. Because of the potential adjustment to the warrant exercise price that could result from this anti-dilution protection, the warrants did not meet the criteria set forth in ASC 815-40, “Derivatives and Hedging — Contracts in Entity’s own Stock” and the Company recorded the fair value of these warrants as a Level 3 liability at the issuance date using the Black-Scholes option pricing model based, in part, on the Company’s assumptions and significant inputs not observed in the market. The Company revalued the warrants at the end of each quarter using the Black-Scholes option pricing model and recognized the change in the fair value of the warrants in the statements of operations and comprehensive loss as other income (expense).
	The sale of shares of Series E preferred stock and Series E warrants in the Company’s November 2012 Series E financing triggered an anti-dilution adjustment under the terms of the Series D warrants, resulting in the exercise price of the Series D warrants being reduced and fixed at the minimum $1.46 per share and the Series D warrants no longer being subject to any anti-dilution adjustments. Since the exercise price of the Series D warrants became fixed, the Series D warrants then met the exception under ASC 815-40 as they were “indexed to the company’s own stock” and met certain criteria for equity classification, thus the Series D warrants were marked to fair value resulting in the recognition of $675,000 of non-operating income during the period ended November 9, 2012 at which time the $503,000 fair value of the warrant liability was transferred to stockholders’ equity.
New Accounting Pronouncements - Recently Issued	(n) New Accounting Pronouncements — Recently Issued
	In April 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-08 —Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The amendments in this ASU require that a disposal representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results or a business activity classified as held for sale should be reported as discontinued operations. The amendments also expand the disclosure requirements for discontinued operations and add new disclosure requirements for individually significant components that do not qualify as discontinued operations. This ASU will be effective prospectively for fiscal years beginning on or after December 15, 2014. Early adoption is permitted, but only for disposals that have not been previously reported in financial statements previously issued. The Company does not expect the adoption of this ASU to have a material effect on its financial statements.
	In May 2014, the FASB issued ASU No. 2014-09 — Revenue from Contracts with Customers (Topic 606). This ASU requires an entity to recognize revenue from the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In particular, this ASU addresses contracts with more than one performance obligation, as well as the accounting for some costs to obtain or fulfill a contract with a customer, and provides for additional disclosures with respect to revenues and cash flows arising from contracts with customers. This ASU will be effective for fiscal years beginning after December 15, 2016. Early adoption of this ASU is not permitted. The Company is currently evaluating the effect that the adoption of this ASU will have on its financial statements.
Accounting for Uncertainty in Income Taxes	The Company applies ASC 740-10, “Accounting for Uncertainty in Income Taxes, an interpretation of ASC 740.” ASC 740-10 clarifies the accounting for uncertainty in income taxes recognized in financial statements and requires the impact of a tax position to be recognized in the financial statements if that position is more likely than not of being sustained by the taxing authority. The Company had no unrecognized tax benefits resulting from uncertain tax positions at December 31, 2014 and 2013.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Change in Accumulated Balance of the Component of Other Comprehensive (Loss) Gain	The following table includes the changes in the accumulated balance of the component of other comprehensive (loss) gain for the years ended December 31, 2014 and 2013:
		Year ended December 31,
	(In thousands)	2014			2013
	Accumulated unrealized loss on available-for-sale securities at beginning of period	$	(7	)	$	—
	Change during the period		(10	)		(7	)
	Accumulated unrealized loss on available-for-sale securities at end of period	$	(17	)	$	(7	)
Schedule of Assumptions Used to Determine Fair Value of Stock Options Granted During Period	The fair value of each option award is estimated on the date of grant using the Black-Scholes option pricing model. The following assumptions apply to the options to purchase 8,232,424, 5,072,583, and 187,500 shares of common stock granted to employees and directors during the years ended December 31, 2014, 2013 and 2012, respectively:
		2014			2013			2012
	Average risk free interest rate		1.4	%		1.3	%		0.8	%
	Expected dividend yield		—			—			—
	Expected lives (years)		4.4			5			5.6
	Expected volatility		86	%		67	%		62	%
	Weighted average grant date fair value of options granted during the period (per share)	$	2.36		$	0.89		$	0.51
	Weighted average exercise price of options granted during the period (per share)	$	3.69		$	1.55		$	0.92
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The table below presents the assets and liabilities measured and recorded in the financial statements at fair value on a recurring basis at December 31, 2014 and 2013 categorized by the level of inputs used in the valuation of each asset and liability.
	(In thousands)	Total			Quoted Prices			Significant			Significant
					in Active			Other			Unobservable
					Markets			Observable			Inputs
					for Identical			Inputs			(Level 3)
					Assets or			(Level 2)
					Liabilities
					(Level 1)
	December 31, 2014
	Assets
	Money market funds	$	17,156		$	17,156		$	—		$	—
	Other cash equivalents – commercial paper		2,500			—			2,500			—
	Short-term investments – commercial paper		4,494			—			4,494			—
	Short-tem investments – certificate of deposit		500			—			500			—
	Short-term investments – corporate bonds		14,357			—			14,357			—
	Short-term investments – municipal bonds		1,905			—			1,905			—
	Long-term investments		7,344			—			7,344			—
	Total Assets	$	48,256		$	17,156		$	31,100		$	—
	Total Liabilities	$	—		$	—		$	—		$	—
	December 31, 2013
	Assets
	Money market funds	$	25,201		$	25,201		$	—		$	—
	Short-term investments – commercial paper		1,997			—			1,997			—
	Short-term investments– corporate bonds		1,128			—			1,128			—
	Long-term investments		6,189			—			6,189			—
	Total Assets	$	34,515		$	25,201		$	9,314		$	—
	Total Liabilities	$	—		$	—		$	—		$	—

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Investments at Fair Value	The Company’s available-for-sale investments at fair value consisted of the following at December 31, 2014 and 2013:
		December 31, 2014
		Cost		Gross			Gross		Estimated
				Unrealized			Unrealized		Fair
				(Losses)			Gains		Value
		(In thousands)
	Commercial paper due in one year or less	$	4,493	$	—		$	1	$	4,494
	Certificate of deposit due in one year or less		500		—			—		500
	Corporate bonds due in one year or less		14,364		(7	)		—		14,357
	Municipal bonds due in one year or less		1,906		(1	)		—		1,905
	Total short-term investments		21,263		(8	)		1		21,256
	Corporate bonds due in one year or more		7,354		(10	)		—		7,344
	Total long-term investments		7,354		(10	)		—		7,344
	Total investments	$	28,617	$	(18	)	$	1	$	28,600
		December 31, 2013
		Cost		Gross			Gross		Estimated
				Unrealized			Unrealized		Fair
				(Losses)			Gains		Value
		(In thousands)
	Commercial paper due in one year or less	$	1,997	$	—		$	—	$	1,997
	Corporate bonds due in one year or less		1,128		—			—		1,128
	Total short-term investments		3,125		—			—		3,125
	Corporate bonds due in one year or more		6,196		(7	)		—		6,189
	Total long-term investments		6,196		(7	)		—		6,189
	Total investments	$	9,321	$	(7	)	$	—	$	9,314

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Tabular Disclosure of Major Components of Property and Equipment and Related Accumulated Depreciation	At December 31, 2014 and 2013, net property and equipment at cost consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Leasehold improvements	$	525	$	525
	Laboratory equipment and other		3,884		2,854
	Total property and equipment, at cost		4,409		3,379
	Less: Accumulated depreciation and amortization		3,103		3,289
	Property and equipment, net	$	1,306	$	90

Note_Payable_and_Accrued_Expen1

Note Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Schedule of Aggregate Future Minimum Payments Due Under Loan and Security Agreement	Aggregate future minimum payments, reflecting payments on outstanding principal plus interest, due under the loan and security agreement as of December 31, 2014, were as follows (in thousands):
	Year ending December 31,
	2015	$	200
	2016		333
	2017		333
	2018		219
	Total minimum payments		1,085
	Less amount representing interest		(192	)
	Notes payable, gross		893
	Unamortized facility fee		(27	)
	Accrual of final payment		4
	Notes payable, balance		870
	Less current portion of notes payable		(128	)
	Non-current portion of notes payable	$	742
Accrued Expenses	At December 31, 2014 and 2013, accrued expenses consisted of the following:
		December 31,
		2014			2013
		(In thousands)
	Payroll and related costs	$	1,453		$	817
	Clinical and nonclinical trial expenses		2,068			1,277
	Cost of regaining rights to cancer program		251			966
	Professional and consulting fees		530			337
	Other		158			109
		$	4,460		$	3,506

Series_D_Convertible_Preferred1

Series D Convertible Preferred Stock and Warrants (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Summary of the Changes in the Series D Preferred Stock	The following is a summary of the changes in the Series D preferred stock during 2012 and 2011 (in thousands):
	Gross proceeds from November 4, 2011 Series D financing (including $351 paid for the warrants)	$	9,500
	Less — allocation of proceeds to:
	Fair value of warrants		(3,152	)
	Beneficial conversion feature		(4,445	)
	Transaction costs		(427	)
	Net proceeds allocated to Series D preferred stock		1,476
	Accretion of beneficial conversion feature		4,445
	Fair value of Series D preferred stock — November 4, 2011	$	5,921
	Fair value of Series D preferred stock — December 31, 2011	$	5,921
	Beneficial conversion feature related to Series E financing		(1,238	)
	Accretion of beneficial conversion feature		1,238
	Fair value of Series D preferred stock — December 31, 2012	$	5,921

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Warrants Outstanding and Exercisable for the Purchase of Common Stock	The Company has the following warrants outstanding and exercisable for the purchase of common stock at December 31, 2014:
	Expiration Date	Shares			Weighted
					Average Exercise
					Price Per share
	August 5, 2015		334,600		$	3.71
	November 4, 2016		2,810,650			1.46
	November 9, 2017		7,484,840			0.7
	May 7, 2018		24,906,327			0.47
	May 7, 2020		15,816,327			0.01
	September 30, 2020		4,175,975			0.01
	February 10, 2021		2,158,750			0.01
	Total		57,687,469			0.39
Summary of Stock Options	The following table summarizes information related to the outstanding and exercisable options during 2014 (in thousands, except per share amounts and years):
		Stock			Weighted-Average		Weighted-Average		Aggregate
		Options			Exercise Price		Remaining		Intrinsic
							Contractual Life		Value
							(in years)
	Outstanding at December 31, 2013		10,148		$	3.38
	Granted		8,232			3.69
	Exercised		(374	)		2.37
	Forfeited		(825	)		2.18
	Expired		(230	)		6.81
	Outstanding at December 31, 2014		16,951			3.56		8.06	$	23,512
	Exercisable at December 31, 2014		7,393			3.95		6.15		11,950
	Total exercisable or expected to vest		16,320			3.57		8		22,749
Summary of the Changes in the Series E Preferred Stock	The following is a summary of the changes in the Series E preferred stock during 2012 (in thousands):
	Gross proceeds from November 9, 2012 Series E financing (including $1,061 paid for the warrants)	$	7,000
	Less — allocation of proceeds to:
	Fair value allocated to warrants		(2,322	)
	Beneficial conversion feature		(1,262	)
	Transaction costs		(977	)
	Net proceeds allocated to Series E preferred stock		2,439
	Accretion of beneficial conversion feature		1,262
	Carrying Value of Series E preferred stock — November 9, 2012	$	3,701
	Carrying Value of Series E preferred stock — December 31, 2012	$	3,701

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Commitments Under Company Lease Agreement	The lease is classified as an operating lease. Future minimum commitments as of December 31, 2014 under the Company’s lease agreement are approximately:
	December 31,	Operating
		Lease
		(In thousands)
	2015	$	1,521
	2016		1,550
	2017		1,046
		$	4,117

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Components of the Deferred Tax Assets	As of December 31, 2014 and 2013, the components of the deferred tax assets are approximately as follows:
		2014			2013
		(In thousands)
	Operating loss carryforwards	$	30,632		$	68,500
	Tax credit carryforwards		2,174			9,376
	Other		5,625			5,078
			38,431			82,954
	Valuation allowance		(38,431	)		(82,954	)
		$	—		$	—
Difference Between the 34% U.S. Federal Corporate Tax Rate and the Company's Effective Tax Rate	The difference between the 34% U.S. federal corporate tax rate and the Company’s effective tax rate is as follows for the years ended December 31, 2014, 2013 and 2012:
		2014			2013			2012
	Expected federal income tax rate		(34.0	)%		(34.0	)%		(34.0	)%
	Expiring credits and NOLs		—			0.2			116.3
	Change in valuation allowance		(115.3	)		43.1			(76.6	)
	Federal and state credits		(4.0	)		(5.0	)		(0.6	)
	State income taxes, net of federal benefit		(5.1	)		(5.1	)		(5.2	)
	Permanent differences		0.8			0.9			0.1
	Section 382 Limitation		157.5			—			—
	Other		0.1			(0.1	)		—
	Effective tax rate		0	%		0	%		0	%

Supplemental_Disclosure_of_Cas1

Supplemental Disclosure of Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosure of Cash Flow Information	Supplemental disclosure of cash flow information for the periods presented is as follows:
		Year Ended December 31,
		2014		2013		2012
		(In thousands)
	Supplemental disclosure of cash flow information:
	Cash paid for interest	$	21	$	—	$	—
	Supplemental disclosure of non-cash financing and investing activities:
	Conversion of Series D preferred stock to common stock	$	5,464	$	—	$	—
	Conversion of Series E preferred stock to common stock	$	5,528	$	—	$	—
	Extinguishment of Series D and Series E preferred stock and issuance of related warrants	$	—	$	5,921	$	—
	Accrued 2013 financing transaction costs paid in 2014	$	—	$	100	$	—
	Accretion of Series D redeemable preferred stock beneficial conversion feature	$	—	$	—	$	1,238
	Accretion of Series E preferred stock beneficial conversion feature	$	—	$	—	$	1,262
	Reclassification of Series D warrants from liabilities to stockholders’ equity	$	—	$	—	$	503

April_2013_Pillar_Agreements_T

April 2013 Pillar Agreements (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Schedule of Assumptions and Other Inputs Used to Compute Fair Value of Agreement Warrants	The Company used the Black-Scholes option pricing model to compute the fair value of the Pillar Warrants as of the May 7, 2013 effective date on which the Pillar Warrants were issued based on the following assumptions and other inputs:
		Pillar I			Additional
		Warrants			Pillar
					Warrants
	Common stock price	$	0.57		$	0.57
	Warrant exercise price	$	0.61		$	0.79
	Term of warrant (years)		5			1.1
	Expected volatility		62	%		67	%
	Average risk free interest rate		0.8	%		0.1	%
	Expected dividend yield		—			—
	Expected percentage of warrants to be exercised		100	%		100	%

Financings_Tables

Financings (Tables)	12 Months Ended
	Dec. 31, 2014
Brokers and Dealers [Abstract]
May 2013 Follow-on Underwritten Public Offering	On May 7, 2013, the Company closed a follow-on underwritten public offering, in which it sold 17,500,000 shares of common stock, together with matching warrants to purchase up to 17,500,000 shares of common stock, and pre-funded warrants to purchase up to 15,816,327 shares of common stock, together with matching warrants to purchase up to 15,816,327 shares of common stock, for aggregate gross proceeds of $16.5 million as follows:
		Combined		Common		Pre-funded		Matching
		Price to the		Stock		Warrants		Warrants
		Public
		(per share of
		Common
		Stock)
	Common stock and matching warrants sold (shares)	$	0.5		17,500,000		—		17,500,000
	Pre-funded warrants and matching warrants sold (shares)	$	0.49		—		15,816,327		15,816,327
	Total (shares)				17,500,000		15,816,327		33,316,327
	Warrant exercise price (per share)		—		—	$	0.01	$	0.47
	Term of warrant (years)		—		—		7		5

Organization_Additional_Inform

Organization - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
	Platform
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of technology platform to develop drug candidates	2
Accumulated deficit	($451,526)	($412,884)

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			36 Months Ended
	Nov. 09, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
		Segment
Accounting Policies [Line Items]
Period of maturities		90 days
Held-to-maturity investments		$0	$0		$0
Realized gains or losses from available-for-sale securities		0	0	0
Losses from investments					0
Auction rate securities		0	0		0
Total restricted cash		311,000	311,000		311,000
Accumulated unrealized gain or loss on available-for-sale securities		-17,000	-7,000	0	-17,000
Number of operating segments		1
Stock-based compensation		4,322,000	1,398,000	2,096,000
Accelerated amortization expense associated to employee's option		1,293,000
Option to purchase common stock granted to employees and directors		8,232,424	5,072,583	187,500
Fair value of options, vested		4,208,000	1,429,000	2,123,000
Intrinsic value of options exercised		573,000	150,000
Options Exercised		374,000		0
Unrecognized compensation cost related to nonvested stock-based compensation		18,669,000			18,669,000
Period for recognition of cost related to nonvested stock-based compensation arrangements		3 years 7 months 6 days
Recognition of gain in other income	675,000
Fair value of warrant liability transferred to stockholders' equity	$503,000			$503,000
Employees [Member]
Accounting Policies [Line Items]
Stock options, vesting period		4 years
Directors [Member]
Accounting Policies [Line Items]
Stock options, vesting period		3 years
Minimum [Member]
Accounting Policies [Line Items]
Equipment depreciation period		3 years
Exercise price of warrants		$1.46			$1.46
Maximum [Member]
Accounting Policies [Line Items]
Equipment depreciation period		5 years

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Change in Accumulated Balance of the Component of Other Comprehensive (Loss) Gain (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Accumulated unrealized loss on available-for-sale securities at beginning of period	($7,000)	$0
Change during the period	-10,000	-7,000
Accumulated unrealized loss on available-for-sale securities at end of period	($17,000)	($7,000)

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Schedule of Assumptions Used to Determine Fair Value of Stock Options Granted During Period (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Average risk free interest rate	1.40%	1.30%	0.80%
Expected dividend yield	0.00%	0.00%	0.00%
Expected lives (years)	4 years 4 months 24 days	5 years	5 years 7 months 6 days
Expected volatility	86.00%	67.00%	62.00%
Weighted average grant date fair value of options granted during the period (per share)	$2.36	$0.89	$0.51
Weighted average exercise price of options granted during the period (per share)	$3.69	$1.55	$0.92

Summary_of_Significant_Account6

Summary of Significant Accounting Policies - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	$48,256	$34,515
Total Liabilities	0	0
Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	17,156	25,201
Short-term Investments - Commercial Paper [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	4,494	1,997
Short-term Investments - Corporate Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	14,357	1,128
Long-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	7,344	6,189
Other Cash Equivalents - Commercial Paper [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	2,500
Short-term Investments - Certificate of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	500
Short - Term Investments - Municipal Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	1,905
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	17,156	25,201
Total Liabilities	0	0
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	17,156	25,201
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	31,100	9,314
Total Liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments - Commercial Paper [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	4,494	1,997
Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments - Corporate Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	14,357	1,128
Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	7,344	6,189
Significant Other Observable Inputs (Level 2) [Member] | Other Cash Equivalents - Commercial Paper [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	2,500
Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments - Certificate of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	500
Significant Other Observable Inputs (Level 2) [Member] | Short - Term Investments - Municipal Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Assets	1,905
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total Liabilities	$0	$0

Investments_Summary_of_Availab

Investments - Summary of Available-for-Sale Investments at Fair Value (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Cost	$28,617	$9,321
Gross Unrealized (Losses)	-18	-7
Gross Unrealized Gains	1
Estimated Fair Value	28,600	9,314
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	21,263	3,125
Gross Unrealized (Losses)	-8
Gross Unrealized Gains	1
Estimated Fair Value	21,256	3,125
Short-term Investments [Member] | Commercial Paper Due in One Year or Less [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	4,493	1,997
Gross Unrealized Gains	1
Estimated Fair Value	4,494	1,997
Short-term Investments [Member] | Certificate of Deposit Due in One Year or Less [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	500
Estimated Fair Value	500
Short-term Investments [Member] | Corporate Bonds Due in One Year or Less [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	14,364	1,128
Gross Unrealized (Losses)	-7
Estimated Fair Value	14,357	1,128
Short-term Investments [Member] | Municipal Bonds Due In One Year Or Less [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	1,906
Gross Unrealized (Losses)	-1
Estimated Fair Value	1,905
Long-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	7,354	6,196
Gross Unrealized (Losses)	-10	-7
Estimated Fair Value	7,344	6,189
Long-term Investments [Member] | Corporate Bonds Due in One Year or More [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	7,354	6,196
Gross Unrealized (Losses)	-10	-7
Estimated Fair Value	$7,344	$6,189

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	12 Months Ended			36 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Realized gains or losses from available-for-sale securities	$0	$0	$0
Auction rate securities, noncurrent	0	0		0
Losses from investments				$0

Property_and_Equipment_Tabular

Property and Equipment - Tabular Disclosure of Major Components of Property and Equipment and Related Accumulated Depreciation (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Abstract]
Leasehold improvements	$525	$525
Laboratory equipment and other	3,884	2,854
Total property and equipment, at cost	4,409	3,379
Less: Accumulated depreciation and amortization	3,103	3,289
Property and equipment, net	$1,306	$90

Property_and_Equipment_Additio

Property and Equipment - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense on property and equipment	$206	$137	$251

Note_Payable_and_Accrued_Expen2

Note Payable and Accrued Expenses - Additional Information (Detail) (Oxford [Member], USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2014
	Installment
Oxford [Member]
Debt Instrument [Line Items]
Borrowing capacity under the Loan & security agreement	$3,000,000
Basis spread on fixed interest rate set at time of advance	7.27%
Minimum interest rate	7.50%
Description of interest rate		Each equipment advance will include interest at a fixed interest rate equal to the greater of 7.5% per annum and 7.27% plus the three-month U.S. Libor Rate per annum
Debt instrument payment terms		The principal amount of each equipment advance will be repaid in 36 monthly installments commencing on the applicable amortization date, which is July 1, 2015 for any equipment advance made on or before June 30, 2015, and is the first monthly payment date for any equipment advance made on or after July 1, 2015. Monthly installments payable prior to July 1, 2015 will consist of accrued interest only and monthly installments payable on or after July 1, 2015 will consist of principal and accrued interest
Debt instrument number of installments that include principal payable	36
Final payment of additional interest as a percentage of aggregate amount advanced		5.70%
Weighted average annual effective interest rate		11.10%
Minimum prepayment fee interest rate percentage		1.00%
Maximum prepayment fee interest rate percentage		3.00%
Advance received under loan and security agreement		893,000
Amount available for borrowing under agreement		$2,107,000
Outstanding loan balance, default interest rate		5.00%

Note_Payable_and_Accrued_Expen3

Note Payable and Accrued Expenses - Schedule of Aggregate Future Minimum Payments Due Under Loan and Security Agreement (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Instruments [Abstract]
2015	$200
2016	333
2017	333
2018	219
Total minimum payments	1,085
Less amount representing interest	-192
Notes payable, gross	893
Unamortized facility fee	-27
Accrual of final payment	4
Notes payable, balance	870
Notes payable, balance	870
Less current portion of notes payable	-128
Non-current portion of notes payable	$742

Note_Payable_and_Accrued_Expen4

Note Payable and Accrued Expenses - Accrued Expenses (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]
Payroll and related costs	$1,453	$817
Clinical and nonclinical trial expenses	2,068	1,277
Cost of regaining rights to cancer program	251	966
Professional and consulting fees	530	337
Other	158	109
Total accrued expenses	$4,460	$3,506

Collaboration_and_License_Agre1

Collaboration and License Agreements - Additional Information (Detail) (USD $)	1 Months Ended				12 Months Ended
	Dec. 31, 2014	31-May-14	Apr. 30, 2014	Dec. 31, 2006	Dec. 31, 2014	Dec. 31, 2010	Dec. 31, 2001
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cumulative proceeds received under antisense license agreements	$1,500,000				$1,500,000
Abbott Molecular [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Paid or expects to pay for external development expenses	2,200,000	6,700,000
Expected agreement term		5 years
Merck Sharp [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License fee paid to company				20,000,000
Proceeds from the sale of common stock under stock purchase agreement				10,000,000
Common stock price				$5.50
Aggregate potential milestones to be received under collaboration - one					165,000,000
Aggregate potential milestones to be received under collaboration - two					260,000,000
Extended revenue recognition period						2 years
Revenue recognition period						4 years
Research collaboration agreement period				2 years
Shares of common stock issued under stock purchase agreement				1,818,182
Maximum amount that may be credited towards any amount due from collaborator for third-party license income received by the Company			60,000,000
Percentage of third-party license income received by the Company that is credited towards any amount due from collaborator			15.00%
Isis Pharmaceuticals [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment to company by Isis in cash							15,000,000
Common stock issued							857,143
Value of common stock received for granting license							17,300,000
Sublicense income received from Isis					300,000
Payment made by company under license agreement					700,000
Shares of the Company's common stock that were issued in the transaction					1,005,499
Value of the Company's common stock that was issued in the transaction					$1,200,000

Series_D_Convertible_Preferred2

Series D Convertible Preferred Stock and Warrants - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended	1 Months Ended	12 Months Ended
	Nov. 09, 2012	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2011	Feb. 06, 2014	Nov. 30, 2012	Dec. 31, 2013	Nov. 30, 2011	Dec. 31, 2010
Schedule of Convertible Preferred Stock [Line Items]
Common shares issued upon conversion		20
Transfer of warrant fair value to stockholders' equity	$503,000		$503,000
Percentage of holding by affiliates upon which warrants may not be exercised		19.99%
Minimum [Member]
Schedule of Convertible Preferred Stock [Line Items]
Exercise price of warrants		1.46
Series D Convertible Redeemable Preferred Stock [Member]
Schedule of Convertible Preferred Stock [Line Items]
Annual percentage of dividend of preferred stock		7.00%
Increase in dividend rate percentage		2.20%
Initial conversion price		1.63
Original purchase price per share available at time of liquidation, dissolution, winding up		8.1375
Common shares issued upon conversion		5.5736						5.5736
Adjusted conversion price		1.46
Maximum beneficial ownership at which dividends may be paid in shares		19.99%
Minimum percentage of preferred stock conversion price for redemption of stock		200.00%
Minimum period used to determine if warrants may be redeemed		20 days
Initial discount on preferred stock resulting in BCF				4,445,000
Additional discount on preferred stock resulting in additional BCF			1,238,000
Original fair value of preferred stock			5,921,000	5,921,000				5,921,000	5,921,000
Redemption value of preferred stock			9,149,000	9,149,000
Additional BCF and dividend accretion if redemption of preferred stock had become probable		3,228,000
Exercise price of warrants		1.63
Minimum closing price of common stock for redemption of warrants		6.51
Warrant redemption price per share		0.01
Transfer of warrant fair value to stockholders' equity	503,000
Series D Convertible Redeemable Preferred Stock [Member] | Minimum [Member]
Schedule of Convertible Preferred Stock [Line Items]
Exercise price of warrants		1.46
Series D Preferred Stock [Member]
Schedule of Convertible Preferred Stock [Line Items]
Shares of common stock issued upon conversion					6,266,175
Shares of Preferred Stock outstanding after conversion					0
Dividends payable		0					160,000
Series E Preferred Stock [Member]
Schedule of Convertible Preferred Stock [Line Items]
Annual percentage of dividend of preferred stock	4.60%		4.60%			4.60%
Percentage of dividends payable in cash quarterly in arrears							8.00%
Dividends payable		0					$119,000

Series_D_Convertible_Preferred3

Series D Convertible Preferred Stock and Warrants - Summary of the Changes in the Series D Preferred Stock (Detail) (Series D Convertible Redeemable Preferred Stock [Member], USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Nov. 30, 2011
Series D Convertible Redeemable Preferred Stock [Member]
Schedule Of Redeemable Convertible Preferred Stock [Line Items]
Fair value of preferred stock, Beginning Balance	$5,921,000	$5,921,000	$5,921,000
Gross proceeds from financing (including $351 paid for warrants)		9,500,000
Beneficial conversion feature related to Series E financing	-1,238,000
Fair value of warrants		-3,152,000
Beneficial conversion feature		-4,445,000
Transaction costs		-427,000
Net proceeds allocated to preferred stock		1,476,000
Accretion of beneficial conversion feature	1,238,000	4,445,000
Fair value of preferred stock, Ending Balance	$5,921,000	$5,921,000	$5,921,000

Series_D_Convertible_Preferred4

Series D Convertible Preferred Stock and Warrants - Summary of the Changes in the Series D Preferred Stock (Parenthetical) (Detail) (Series D Convertible Redeemable Preferred Stock [Member], USD $)	Dec. 31, 2011
In Thousands, unless otherwise specified
Series D Convertible Redeemable Preferred Stock [Member]
Schedule Of Redeemable Convertible Preferred Stock [Line Items]
Aggregate purchase price of warrants	$351

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended	0 Months Ended		1 Months Ended	0 Months Ended		12 Months Ended		1 Months Ended
	Sep. 30, 2013	Dec. 31, 2014	Nov. 09, 2012	7-May-13	Dec. 31, 2014	Feb. 10, 2014	5-May-98	Dec. 31, 2013	Dec. 31, 2012	Nov. 30, 2012
Changes In Equity And Comprehensive Income Line Items [Line Items]
Stock issued, shares	13,727,251
Shares held by put holders		35,780
Remaining shares of common stock subject to the liquidation put		763,954
Additional number of common shares		5,720,540
Minimum option exercise price as a percentage of fair value of common stock		100.00%
Common stock options outstanding		16,951,000			16,951,000			10,148,000
Common shares available for grant		2,516,500			2,516,500
Options outstanding under earlier plans		6,406,439			6,406,439
Grant of inducement stock option		2,600,000
Preferred stock, shares authorized		5,000,000			5,000,000			5,000,000
Preferred stock, par value		$0.01			0.01			0.01
Series A preferred stock liquidation preference per share		$1			1
Series A Preferred stock conversion price per share		$34			34
Percentage Series E shareholder consent needed to dilute protective provisions		51.00%
Percentage of outstanding common stock		19.99%
Series E Preferred stock, convertible into common stock		20			20
Minimum number of trading days used to determine if Series E preferred stock may be redeemed		20 days
Trading days of common stock		30 days
Minimum percentage of Series E preferred stock conversion price for redemption of stock		400.00%
Series E Warrant [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Fair value of Series E warrants			$2,949,000
Fair value of warrants			2,322,000
2013 Stock Incentive Plan [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Stock options, expiration period		10 years
Shares of common stock that may be issued under 2013 Stock Incentive Plan		10,224,460			10,224,460
Maximum number of shares that may be granted to any one individual in single year		1,500,000
Minimum [Member] | 2013 Stock Incentive Plan [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Stock options, vesting period		3 years
Maximum [Member] | 2013 Stock Incentive Plan [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Stock options, vesting period		4 years
Common Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Stock issued, shares				17,500,000
Shares of common stock issued upon conversion of Series E preferred stock					8,484,840
Common Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Stock issued, shares						7,867,438	1,199,684
Sale price of common shares subject to the liquidation put		$16
Minimum closing sales price of common stock to issue termination notice to put holders		$32
Price exceeds on number of days		20 days
Liquidation put shares no longer held by original holders		399,950
Employee Stock Purchase Plan [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Common stock shares authorized for issuance under stock purchase plan		500,000			500,000
Minimum Percentage Voting Stock that Prevents Employee Stock Purchase Plan Participation		5.00%
Percentage of fair market value of common stock used as Employee Stock Purchase Plan option price		85.00%
Minimum % of participating employee's base pay that may be used to purchase stock under Employee Stock Purchase Plan during an offering period		1.00%
Maximum % of participating employee's base pay that may be used to purchase stock under Employee Stock Purchase Plan during an offering period		10.00%
Percentage of Market Value of Common Stock on Commencement of Offering Period		85.00%
Maximum % of employee defined annualized base pay that may be used to purchase stock under Employee Stock Purchase Plan		15.00%
Common stock share issued		13,844						14,716	4,746
Series A Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Preferred stock, par value		$0.01			0.01			0.01
Preferred stock, shares designated		1,500,000			1,500,000			1,500,000
Annual percentage of dividend of preferred stock		1.00%
Preferred stock, shares outstanding		1,000			1,000			1,000
Preferred stock, shares issued		1,000			1,000			1,000
Series D Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Preferred stock, par value		$0.01			0.01			0.01
Preferred stock, shares designated		0			0			1,124,000
Preferred stock, shares outstanding		0			0			1,124,000
Preferred stock, shares issued		0			0			1,124,000
Dividends payable		0			0			160,000
Series E Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Stock issued, shares									424,000
Preferred stock, par value		$0.01			0.01			0.01
Preferred stock, shares designated		424,000			424,000			424,000
Annual percentage of dividend of preferred stock			4.60%						4.60%	4.60%
Preferred stock, shares outstanding		0			0			424,000	424,000
Preferred stock, shares issued		0	424,242		0			424,000		424,242
Preferred stock dividend rate percentage if shareholders approve		8.00%
Dividends payable		0			0			119,000
Minimum number of shares of Series E preferred stock outstanding to maintain protective provisions		84,849
Series E preferred stock conversion price		$0.70
Purchase price of the Series E preferred stock		$14			14
Fair value of warrants									2,322,000
Beneficial conversion feature			$1,262,000						1,262,000
Series E Preferred Stock [Member] | Series E Warrant [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Series E warrants issued, shares		8,484,840

Stockholders_Equity_Warrants_O

Stockholders' Equity - Warrants Outstanding and Exercisable for the Purchase of Common Stock (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Class of Warrant or Right [Line Items]
Shares	57,687,469
Weighted average exercise price of warrants	$0.39
Class of Warrant One [Member]
Class of Warrant or Right [Line Items]
Expiration Date	5-Aug-15
Shares	334,600
Weighted average exercise price of warrants	$3.71
Class of Warrant Two [Member]
Class of Warrant or Right [Line Items]
Expiration Date	4-Nov-16
Shares	2,810,650
Weighted average exercise price of warrants	$1.46
Class of Warrant Three [Member]
Class of Warrant or Right [Line Items]
Expiration Date	9-Nov-17
Shares	7,484,840
Weighted average exercise price of warrants	$0.70
Class of Warrant Four [Member]
Class of Warrant or Right [Line Items]
Expiration Date	7-May-18
Shares	24,906,327
Weighted average exercise price of warrants	$0.47
Class of Warrant Five [Member]
Class of Warrant or Right [Line Items]
Expiration Date	7-May-20
Shares	15,816,327
Weighted average exercise price of warrants	$0.01
Class of Warrant Six [Member]
Class of Warrant or Right [Line Items]
Expiration Date	30-Sep-20
Shares	4,175,975
Weighted average exercise price of warrants	$0.01
Class of Warrant Seven [Member]
Class of Warrant or Right [Line Items]
Expiration Date	10-Feb-21
Shares	2,158,750
Weighted average exercise price of warrants	$0.01

Stockholders_Equity_Summary_of

Stockholders' Equity - Summary of Stock Options (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity [Abstract]
Options, Outstanding, Beginning Balance	10,148,000
Granted	8,232,000
Exercised	-374,000		0
Forfeited	-825,000
Expired	-230,000
Options, Outstanding, Ending Balance	16,951,000	10,148,000
Exercisable, Ending Balance	7,393,000
Total exercisable or expected to vest	16,320,000
Weighted Average Exercise Price, Beginning Balance	$3.38
Granted, Weighted Average Exercise Price	$3.69	$1.55	$0.92
Exercised, Weighted Average Exercise Price	$2.37
Forfeited, Weighted Average Exercise Price	$2.18
Expired, Weighted Average Exercise Price	$6.81
Weighted Average Exercise Price, Ending Balance	$3.56	$3.38
Exercisable, Weighted Average Exercise Price	$3.95
Total exercisable or expected to vest, Weighted Average Exercise Price	$3.57
Outstanding, Ending balance, Weighted Average Remaining Contractual Term	8 years 22 days
Exercisable Ending Balance, Weighted Average Remaining Contractual Term	6 years 1 month 24 days
Total exercisable or expected to vest, Weighted Average Remaining Contractual Term	8 years
Outstanding, Intrinsic Value, Ending Balance	$23,512
Exercisable, Ending Balance, Intrinsic Value	11,950
Total exercisable or expected to vest, Aggregate Intrinsic Value	$22,749

Stockholders_Equity_Summary_of1

Stockholders' Equity - Summary of the Changes in the Series E Preferred Stock (Detail) (Series E Preferred Stock [Member], USD $)	0 Months Ended	12 Months Ended
	Nov. 09, 2012	Dec. 31, 2012	Nov. 09, 2012
Series E Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Gross proceeds from November 9, 2012 Series E financing (including $1,061 paid for the warrants)		$7,000,000
Fair value allocated to warrants		-2,322,000
Beneficial conversion feature	-1,262,000	-1,262,000
Transaction costs		-977,000
Net proceeds allocated to Series E preferred stock		2,439,000
Accretion of beneficial conversion feature		1,262,000
Carrying Value of Series E preferred stock	$3,701,000	$3,701,000	$3,701,000

Stockholders_Equity_Summary_of2

Stockholders' Equity - Summary of the Changes in the Series E Preferred Stock (Parenthetical) (Detail) (Series E Preferred Stock [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2012
Series E Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Amount paid for warrants	$1,061

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended		12 Months Ended			0 Months Ended
	7-May-13	Nov. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
		Shareholder
		Director
Contingencies And Commitments [Line Items]
Rent expense, including real estate taxes			$1,672,000	$1,601,000	$1,596,000
Cash restricted for a security deposit			311,000
Period of renewal option exercisable by the Company			3 years
Operating lease expiration date			31-Aug-17
Annual minimum payments due, 2015			10,000
Annual minimum payments due, 2016			10,000
Future minimum commitments under agreement, total			2,246,000
Number of directors managing investment decision		2
Number of significant shareholder managing investment decision		1
Number of shares of common stock sold in financing	17,500,000
Warrant to purchase common stock			57,687,469
Directors consulting fees			0	0	1,000
Proceeds from issuance of common stock in lieu of director board and committee fees			82,000	26,000	1,000
Common Stock and Matching Warrants Sold [Member]
Contingencies And Commitments [Line Items]
Number of shares of common stock sold in financing	17,500,000
Pillar Three Entities [Member]
Contingencies And Commitments [Line Items]
Exercise price of warrants	0.47
Aggregate purchase price	2,500,000
Pillar Three Entities [Member] | Common Stock and Matching Warrants Sold [Member]
Contingencies And Commitments [Line Items]
Number of shares of common stock sold in financing	5,000,000
Warrant to purchase common stock	5,000,000
Pillar Four Entities [Member]
Contingencies And Commitments [Line Items]
Number of shares of common stock sold in financing						1,774,193
Aggregate purchase price						$2,750,000

Commitments_and_Contingencies_2

Commitments and Contingencies - Future Minimum Commitments Under Company Lease Agreement (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$1,521
2016	1,550
2017	1,046
Total	$4,117

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax [Line Items]
Period over which NOL and tax credit carryforward limitations are applied	1 year
Period of cumulative changes in ownership	3 years
Cumulative changes in ownership	50.00%
Operating loss carryforwards expiration year	2034
Federal corporate tax rate	-34.00%	-34.00%	-34.00%
Unrecognized tax benefits from uncertain tax	$0	$0
Years not subject to income tax examination	Tax examinations for years before 2011
Period over which material changes in unrecognized tax positions are not expected	12 months
Federal [Member]
Income Tax [Line Items]
Cumulative net operating loss carryforwards	79,112,000
Tax credit carryforwards	1,680,000
Tax credit carryforward expiration year	2034
Excess tax benefit deductions related to the exercise of stock options	670,000
State [Member]
Income Tax [Line Items]
Cumulative net operating loss carryforwards	75,395,000
Tax credit carryforwards	749,000
Tax credit carryforward expiration year	2029
Excess tax benefit deductions related to the exercise of stock options	$349,000

Income_Taxes_Components_of_the

Income Taxes - Components of the Deferred Tax Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]
Operating loss carryforwards	$30,632	$68,500
Tax credit carryforwards	2,174	9,376
Other	5,625	5,078
Deferred Tax Assets, Gross	38,431	82,954
Valuation allowance	-38,431	-82,954
Deferred Tax Assets, Net	$0	$0

Income_Taxes_Difference_Betwee

Income Taxes - Difference Between the 34% U.S. Federal Corporate Tax Rate and the Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Expected federal income tax rate	-34.00%	-34.00%	-34.00%
Expiring credits and NOLs		0.20%	116.30%
Change in valuation allowance	-115.30%	43.10%	-76.60%
Federal and state credits	-4.00%	-5.00%	-0.60%
State income taxes, net of federal benefit	-5.10%	-5.10%	-5.20%
Permanent differences	0.80%	0.90%	0.10%
Section 382 Limitation	157.50%
Other	0.10%	-0.10%
Effective tax rate	0.00%	0.00%	0.00%

Employee_Benefit_Plan_Addition

Employee Benefit Plan - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation and Retirement Disclosure [Abstract]
Maximum employer match as a percentage of base pay	3.00%
Portion of the first 6% of employees' contributions	50.00%
Portion of the Employee's base salary that the Company matches	6.00%
Employer matching contributions to the plan	$139,000	$83,000	$106,000

Net_Loss_per_Common_Share_Appl1

Net Loss per Common Share Applicable to Common Stockholders - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Total antidilutive securities	74,640,383	85,973,681
Preferred stock extinguishment loss and dividends	$519,000	$2,866,000	$3,210,000
Series D and E Preferred Stock [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Loss on extinguishment of convertible preferred stock		1,750,000
Series D Preferred Stock [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Preferred stock extinguishment loss and dividends	66,000	756,000
Series E Preferred Stock [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Preferred stock extinguishment loss and dividends	$453,000	$360,000

Supplemental_Disclosure_of_Cas2

Supplemental Disclosure of Cash Flow Information - Supplemental Disclosure of Cash Flow Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental disclosure of cash flow information:
Cash paid for interest	$21
Supplemental disclosure of non-cash financing and investing activities:
Accrued 2013 financing transaction costs paid in 2014		100
Series D Preferred Stock [Member]
Supplemental disclosure of non-cash financing and investing activities:
Conversion of preferred stock to common stock	5,464
Series E Preferred Stock [Member]
Supplemental disclosure of non-cash financing and investing activities:
Conversion of preferred stock to common stock	5,528
Accretion of Series E preferred stock beneficial conversion feature			1,262
Series D and E Preferred Stock [Member]
Supplemental disclosure of non-cash financing and investing activities:
Extinguishment of Series D and Series E preferred stock and issuance of related warrants		5,921
Series D Convertible Redeemable Preferred Stock [Member]
Supplemental disclosure of non-cash financing and investing activities:
Accretion of Series D redeemable preferred stock beneficial conversion feature			1,238
Series D Warrant [Member]
Supplemental disclosure of non-cash financing and investing activities:
Reclassification of Series D warrants from liabilities to stockholders' equity			$503

April_2013_Pillar_Agreements_A

April 2013 Pillar Agreements - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended	0 Months Ended	1 Months Ended
	7-May-13	Dec. 31, 2014	Apr. 22, 2013	Apr. 30, 2013	Dec. 31, 2013
Effects of Agreements [Line Items]
Minimum closing price to redeem the warrants	2.8
Redemption price per share of warrants	0.01
Fair value of the Pillar Warrants in equity	$380,000
Extinguishment loss which was immediately charged to net loss applicable to common stockholders	1,750,000
Increase in stockholders equity resulting from preferred stock extinguishment and warrant issuance	5,921,000
Minimum period for determining expected volatility		3 years
Percentage of holding by affiliates above which warrants may not be exercised		19.99%
Pillar I Warrants [Member]
Effects of Agreements [Line Items]
Number of Shares of Common Stock Callable By Pillar Warrants			1,000,000
Class of Warrant or Right Exercise Price Per Share of Warrants or Rights			0.61
Minimum closing price to redeem the warrants			2.8
Redemption price per share of warrants			0.01
Additional Pillar Warrants [Member]
Effects of Agreements [Line Items]
Number of Shares of Common Stock Callable By Pillar Warrants				1,000,000
Class of Warrant or Right Exercise Price Per Share of Warrants or Rights				0.79
Final exercise date of warrant				1-Jun-14
Series D Preferred Stock [Member]
Effects of Agreements [Line Items]
Carrying value of preferred stock prior to extinguishment	5,921,000
Carrying value of preferred stock	5,464,000				5,464,000
Series E Preferred Stock [Member]
Effects of Agreements [Line Items]
Carrying value of preferred stock prior to extinguishment	3,701,000
Carrying value of preferred stock	$5,528,000				$5,528,000
April 2013 Pillar Agreements [Member]
Effects of Agreements [Line Items]
Number of agreements				2
April 2013 Pillar Agreements [Member] | Series D Preferred Stock [Member] | Minimum [Member]
Effects of Agreements [Line Items]
Unaffiliated ownership % that would trigger the right to require the Company to repurchase stock that was waived by Pillar Agreement				66.67%
April 2013 Pillar Agreements [Member] | Series E Preferred Stock [Member]
Effects of Agreements [Line Items]
Percentage of preferred stock holders who waived right to receive specified amount in liquidation				100.00%

April_2013_Pillar_Agreements_S

April 2013 Pillar Agreements - Schedule of Assumptions and Other Inputs Used to Compute Fair Value of Agreement Warrants (Detail) (USD $)	0 Months Ended
	7-May-13	7-May-13
Pillar I Warrants [Member]
Assumptions used to compute fair value of Pillar warrants [Line Items]
Common stock price	$0.57	$0.57
Warrant exercise price	$0.61	$0.61
Term of warrant (years)	5 years
Expected volatility	62.00%
Average risk free interest rate	0.80%
Expected dividend yield	0.00%
Expected percentage of warrants to be exercised	100.00%	100.00%
Additional Pillar Warrants [Member]
Assumptions used to compute fair value of Pillar warrants [Line Items]
Common stock price	$0.57	$0.57
Warrant exercise price	$0.79	$0.79
Term of warrant (years)	1 year 1 month 6 days
Expected volatility	67.00%
Average risk free interest rate	0.10%
Expected dividend yield	0.00%
Expected percentage of warrants to be exercised	100.00%	100.00%

Financings_Additional_Informat

Financings - Additional Information 1 (Detail) (USD $)	0 Months Ended		1 Months Ended	0 Months Ended
In Millions, except Share data, unless otherwise specified	Feb. 10, 2014	7-May-13	Sep. 30, 2013	5-May-98	Dec. 31, 2014
Class of Stock [Line Items]
Stock issued, shares			13,727,251
Shares of common stock that may be purchased upon exercise of warrants					57,687,469
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any	$40.10	$16.50	$27.70
Price to the public per share of common stock			$1.55
Sales price per share of pre-funded warrants	$3.99		$1.54
Estimated net proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any	$37.20
Common Stock [Member]
Class of Stock [Line Items]
Stock issued, shares	7,867,438			1,199,684
Price to the public per share of common stock	$4
Pre-funded Warrants [Member]
Class of Stock [Line Items]
Shares of common stock that may be purchased upon exercise of warrants	2,158,750	15,816,327	4,175,975
Exercise price of warrants	$0.01	$0.01	$0.01
Pre-funded warrants expiration date	10-Feb-21		30-Sep-20

Financings_Additional_Informat1

Financings - Additional Information 2 (Detail) (USD $)	0 Months Ended		1 Months Ended
In Millions, except Share data, unless otherwise specified	Feb. 10, 2014	7-May-13	Sep. 30, 2013	Dec. 31, 2014	Feb. 10, 2014
Class of Stock [Line Items]
Shares of common stock sold to investors			13,727,251
Shares of common stock that may be purchased upon exercise of warrants				57,687,469
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any	$40.10	$16.50	$27.70
Price to the public per share of common stock			$1.55
Sales price per share of pre-funded warrants	$3.99		$1.54		$3.99
Net proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any		$14.50	$25.70
Pre-funded Warrants [Member]
Class of Stock [Line Items]
Shares of common stock that may be purchased upon exercise of warrants	2,158,750	15,816,327	4,175,975		2,158,750
Exercise price of warrants	$0.01	$0.01	$0.01		$0.01
Pre-funded warrants expiration date	10-Feb-21		30-Sep-20

Financings_Additional_Informat2

Financings - Additional Information 3 (Detail) (USD $)	0 Months Ended		1 Months Ended
In Millions, except Share data, unless otherwise specified	Feb. 10, 2014	7-May-13	Sep. 30, 2013	Dec. 31, 2014
Class of Stock [Line Items]
Stock issued, shares			13,727,251
Total (shares)				57,687,469
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any	$40.10	$16.50	$27.70
Pre-funded Warrants [Member]
Class of Stock [Line Items]
Total (shares)		15,816,327
Matching Warrants [Member]
Class of Stock [Line Items]
Total (shares)		33,316,327
Matching Warrants [Member] | Pre-funded Warrants [Member]
Class of Stock [Line Items]
Total (shares)		15,816,327
Common Stock [Member]
Class of Stock [Line Items]
Stock issued, shares		17,500,000
Common Stock [Member] | Matching Warrants [Member]
Class of Stock [Line Items]
Total (shares)		17,500,000

Financings_May_2013_Followon_U

Financings - May 2013 Follow-on Underwritten Public Offering (Detail) (USD $)	0 Months Ended
	7-May-13	Dec. 31, 2014	Feb. 10, 2014	Sep. 30, 2013
Class of Warrant or Right [Line Items]
Number of shares of common stock sold in financing	17,500,000
Total (shares)		57,687,469
Common Stock and Matching Warrants Sold [Member]
Class of Warrant or Right [Line Items]
Combined price to the public (per share of common stock)	0.5
Number of shares of common stock sold in financing	17,500,000
Pre-funded Warrants & Matching Warrants Sold [Member]
Class of Warrant or Right [Line Items]
Combined price to the public (per share of common stock)	0.49
Matching Warrants [Member]
Class of Warrant or Right [Line Items]
Total (shares)	33,316,327
Warrant exercise price (per share)	0.47
Term of warrant (years)	5 years
Matching Warrants [Member] | Common Stock and Matching Warrants Sold [Member]
Class of Warrant or Right [Line Items]
Total (shares)	17,500,000
Matching Warrants [Member] | Pre-funded Warrants & Matching Warrants Sold [Member]
Class of Warrant or Right [Line Items]
Total (shares)	15,816,327
Pre-funded Warrants [Member]
Class of Warrant or Right [Line Items]
Total (shares)	15,816,327		2,158,750	4,175,975
Warrant exercise price (per share)	0.01		$0.01	$0.01
Term of warrant (years)	7 years
Pre-funded Warrants [Member] | Pre-funded Warrants & Matching Warrants Sold [Member]
Class of Warrant or Right [Line Items]
Total (shares)	15,816,327

Financings_Additional_Informat3

Financings - Additional Information 4 (Detail) (USD $)	0 Months Ended	1 Months Ended
In Millions, unless otherwise specified	7-May-13	Sep. 30, 2013	7-May-13
Equity [Abstract]
Net proceeds from sale of common stock and warrants excluding the proceeds from future exercise of the warrants, if any	$14.50	$25.70
Redemption price per share of warrants	0.01
Notice period to holder prior to redemption of warrants by Company	30 days
Minimum trading days considered to redeem warrants	20 days
Maximum trading days considered to redeem warrants	30 days
Minimum closing price to redeem the warrants			2.8

Financings_Additional_Informat4

Financings - Additional Information 5 (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity [Abstract]
Proceeds from exercise of warrants	$7,534,000	$3,365,000
Shares issued on exercise of warrants during the period	5,543,802	7,160,000	0

Financings_Additional_Informat5

Financings - Additional Information 6 (Detail) (USD $)	0 Months Ended		1 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Nov. 30, 2012	Nov. 09, 2012	Nov. 30, 2012	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013	Nov. 09, 2012
Class of Stock [Line Items]
Warrants to purchase shares of common stock				57,687,469
Series E Warrant [Member]
Class of Stock [Line Items]
Initial conversion price of preferred stock and exercise price of warrants			$0.70
Class of warrant or right expiration date			9-Nov-17
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Aggregate purchase price of series E			$7
Preferred stock, shares issued	424,242	424,242	424,242	0		424,000	424,242
Warrants to purchase shares of common stock	8,484,840		8,484,840
Common stock conversion price			$0.70
Dividends payable in arrears to the holders of preferred stock		4.60%	4.60%		4.60%
Increased preferred dividend rate			8.00%
Net proceeds from issuance of preferred stock	$6
Percentage of penalty				10.00%

Financings_Additional_Informat6

Financings - Additional Information 7 (Detail) (USD $)	1 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Nov. 30, 2011	Dec. 31, 2014
Class of Stock [Line Items]
Warrants to purchase shares of common stock		57,687,469
Adjusted conversion ratio to common stock		20
Warrant [Member]
Class of Stock [Line Items]
Warrants to purchase shares of common stock	2,810,650
Series D Warrant [Member]
Class of Stock [Line Items]
Initial conversion price of preferred stock and exercise price of warrants	$1.63
Series D Convertible Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Aggregate purchase price under agreement	$9.50
Preferred stock, shares issued	1,124,260
Convertible preferred stock shares upon conversion	5,621,300
Initial conversion price	$1.63
Adjusted conversion price per share	$1.46
Adjusted conversion ratio to common stock	5.5736	5.5736
Net proceeds from issuance of preferred stock	$9.10
Percentage of penalty		10.00%
Series D Convertible Redeemable Preferred Stock [Member] | Maximum [Member]
Class of Stock [Line Items]
Convertible preferred stock shares upon conversion	6,266,175

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	1 Months Ended	0 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Feb. 19, 2015	Dec. 31, 2014	Feb. 10, 2014	7-May-13
Subsequent Event [Line Items]
Stock issued, shares	13,727,251
Shares of common stock that may be purchased upon exercise of warrants			57,687,469
Subsequent Events [Member]
Subsequent Event [Line Items]
Stock issued, shares		23,000,000
Common stock, price per share		$3.75
Gross proceeds from common stocks sold		$86.30
Net proceeds from common stocks sold		$80.60
Investment Funds [Member] | Directors [Member] | Subsequent Events [Member]
Subsequent Event [Line Items]
Stock issued, shares		5,333,333
Common stock, price per share		$3.75
Baker Bros. Advisors LP [Member] | Subsequent Events [Member]
Subsequent Event [Line Items]
Common stock held, shares		6,965,432
Shares of common stock that may be purchased upon exercise of warrants		20,316,327
Warrant exercise price per share		$0.47
Pre-funded Warrants [Member]
Subsequent Event [Line Items]
Shares of common stock that may be purchased upon exercise of warrants	4,175,975			2,158,750	15,816,327
Warrant exercise price per share	0.01			$0.01	$0.01
Pre-funded Warrants [Member] | Baker Bros. Advisors LP [Member] | Subsequent Events [Member]
Subsequent Event [Line Items]
Shares of common stock that may be purchased upon exercise of warrants		22,151,052
Warrant exercise price per share		$0.01