Endocyte (ECYT) 10-K 13 Mar 15 2014 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 27, 2015	Jun. 30, 2014
Document Information [Line Items]
Entity Registrant Name	ENDOCYTE INC
Entity Central Index Key	1235007
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Trading Symbol	ECYT
Entity Common Stock, Shares Outstanding		41,887,010
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2014
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$244.60

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$45,533,443	$52,846,940
Short-term investments	79,536,211	70,434,148
Receivables	706,403	6,353,180
Prepaid expenses	609,771	3,200,924
Other assets	652,510	496,338
Total current assets	127,038,338	133,331,530
Long-term investments	81,761,177	25,571,659
Property and equipment, net	3,970,665	3,839,426
Other noncurrent assets	31,194	114,961
Total assets	212,801,374	162,857,576
Current liabilities:
Accounts payable	1,234,759	5,435,473
Accrued wages and benefits	2,567,924	3,065,905
Accrued clinical trial expenses	2,336,645	3,728,015
Accrued expenses	692,526	1,668,944
Deferred revenue	50,000	59,746,952
Current portion of other liabilities	3,142	18,168
Total current liabilities	6,884,996	73,663,457
Other liabilities, net of current portion	30,316	33,458
Deferred revenue, net of current portion	881,944	931,940
Total liabilities	7,797,256	74,628,855
Liabilities and Stockholders’ Equity
Common stock: $0.001 par value, 100,000,000 shares authorized; 36,155,509 and 41,784,692 shares issued and outstanding at December 31, 2013 and 2014	41,785	36,156
Additional paid-in capital	373,571,500	262,060,590
Accumulated other comprehensive income	-143,928	56,691
Retained deficit	-168,465,239	-173,924,716
Total stockholders' equity	205,004,118	88,228,721
Total liabilities and stockholders' equity	$212,801,374	$162,857,576

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	41,784,692	36,155,509
Common stock, shares outstanding	41,784,692	36,155,509

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue:
Collaboration revenue	$70,353,483	$64,870,919	$34,682,111
Total revenue	70,353,483	64,870,919	34,682,111
Operating expenses:
Research and development	41,649,389	57,898,971	35,670,418
General and administrative	23,677,366	25,313,731	15,054,369
Total operating expenses	65,326,755	83,212,702	50,724,787
Income (loss) from operations	5,026,728	-18,341,783	-16,042,676
Other income (expense), net:
Interest income	578,636	465,505	327,745
Interest expense	-1,189	-2,458	-628,993
Other income (expense), net	-144,698	-153,702	-947,834
Net income (loss)	5,459,477	-18,032,438	-17,291,758
Net income (loss) per share:
Basic (in dollars per share)	$0.14	($0.50)	($0.48)
Diluted (in dollars per share)	$0.13	($0.50)	($0.48)
Items included in other comprehensive income (loss):
Unrealized gain (loss) on foreign currency translation	-38,776	-6,805	707
Unrealized gain (loss) on available-for-sale securities	-161,843	-9,253	78,306
Other comprehensive income (loss)	-200,619	-16,058	79,013
Comprehensive income (loss)	$5,258,858	($18,048,496)	($17,212,745)
Weighted-average number of common shares used in net income (loss) per share calculation:
Basic (in shares)	40,242,352	36,036,996	35,858,757
Diluted (in shares)	41,758,101	36,036,996	35,858,757

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (DEFICIT) (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Balances at Dec. 31, 2012	$99,573,278	$35,919	$255,356,888	$72,749	($155,892,278)
Balances (in shares) at Dec. 31, 2012		35,919,019
Exercise of stock options	644,934	189	644,745	0	0
Exercise of stock options (in shares)	188,699	188,699
Exercise of warrants	0	48	-48	0	0
Exercise of warrants (in shares)		47,791
Stock-based compensation	6,059,005	0	6,059,005	0	0
Stock-based compensation (in shares)		0
Net income (loss)	-18,032,438	0	0	0	-18,032,438
Unrealized loss on foreign exchange translation	-6,805	0	0	-6,805	0
Unrealized loss on securities	-9,253	0	0	-9,253	0
Balances at Dec. 31, 2013	88,228,721	36,156	262,060,590	56,691	-173,924,716
Balances (in shares) at Dec. 31, 2013		36,155,509
Exercise of stock options	1,290,886	400	1,290,486	0	0
Exercise of stock options (in shares)	399,654	399,654
Stock-based compensation	8,021,447	1	8,021,446	0	0
Stock-based compensation (in shares)		1,279
Net income (loss)	5,459,477	0	0	0	5,459,477
Employee stock purchase plan	299,229	53	299,176	0	0
Employee Stock Purchase Plan (in shares)		53,250
Issuance of common stock in connection with secondary offering	101,904,977	5,175	101,899,802	0	0
Issuance of common stock in connection with secondary offering (in shares)		5,175,000
Unrealized loss on foreign exchange translation	-38,776	0	0	-38,776	0
Unrealized loss on securities	-161,843	0	0	-161,843	0
Balances at Dec. 31, 2014	$205,004,118	$41,785	$373,571,500	($143,928)	($168,465,239)
Balances (in shares) at Dec. 31, 2014		41,784,692

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities
Net income (loss)	$5,459,477	($18,032,438)	($17,291,758)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation	857,055	674,725	358,367
Stock-based compensation	8,025,261	6,059,005	3,022,693
Loss on disposal of property and equipment	6,100	1,778	6,354
Loss on extinguishment of debt	0	0	992,281
Accretion of bond premium	1,615,063	1,246,143	961,271
Non cash interest expense	0	0	73,914
Change in operating assets and liabilities:
Receivables	5,490,605	-2,508,687	-1,409,738
Prepaid expenses and other assets	2,711,331	2,016,928	-1,287,834
Accounts payable	-3,700,175	-386,241	524,936
Accrued interest, wages, benefits and other liabilities	-2,923,537	1,337,021	3,483,896
Deferred revenue	-59,746,948	-41,488,719	99,757,129
Net cash provided by (used in) operating activities	-42,205,768	-51,080,485	89,191,511
Investing activities
Purchases of property and equipment	-1,501,744	-827,839	-1,862,872
Proceeds from disposal of property and equipment	10,000	0	0
Purchases of investments	-149,370,678	-125,026,602	-265,203,590
Proceeds from sales and maturities of investments	82,302,191	195,146,871	163,671,395
Net cash provided by (used in) investing activities	-68,560,231	69,292,430	-103,395,067
Financing activities
Stock repurchase	-3,814	0	0
Principal payments on borrowings	0	0	-13,544,175
Proceeds from third public offering, net of issuance costs	101,904,977	0	0
Proceeds from the exercise of stock options	1,290,886	644,934	391,407
Proceeds from stock purchase under employee stock purchase plan	299,229	0	0
Net cash provided by (used in) financing activities	103,491,278	644,934	-13,152,768
Effect of exchange rate	-38,776	-6,805	707
Net increase (decrease) in cash and cash equivalents	-7,313,497	18,850,074	-27,355,617
Cash and cash equivalents at beginning of period	52,846,940	33,996,866	61,352,483
Cash and cash equivalents at end of period	$45,533,443	$52,846,940	$33,996,866

Nature_of_Business_and_Organiz

Nature of Business and Organization	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. Nature of Business and Organization
	Endocyte, Inc. (the “Company”) is a biopharmaceutical company developing targeted therapies for the treatment of cancer and inflammatory diseases. The Company uses its proprietary technology to create novel small molecule drug conjugates (“SMDCs”), and companion imaging agents. The SMDCs actively target receptors that are over-expressed on diseased cells, relative to healthy cells. This targeted approach is designed to enable the treatment of patients with a highly active drug at greater doses, delivered more frequently, and over longer periods of time than would be possible with the untargeted drug alone. The Company is also developing companion imaging agents for each of its SMDCs that are designed to identify the patients whose disease over-expresses the target of the therapy and who are therefore most likely to benefit from treatment.
	The Company has two wholly-owned subsidiaries, Endocyte Europe B.V. and Endocyte Europe GmbH, which were formed to assist with the administration of applications with the European Commission (“EC”) and commercial pre-launch activities in Europe. The applications were withdrawn in May 2014 and the commercial pre-launch activities in Europe ceased. The Company is in the process of dissolving Endocyte Europe GmbH, which should be completed in the first half of 2015. There are no current plans to dissolve Endocyte Europe B.V.
	Public Offerings
	On April 2, 2014, the Company completed a public offering of 5,175,000 shares of its common stock in a public offering. Proceeds, net of underwriting discounts, commissions and other transaction costs, were $101.9 million.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	2. Significant Accounting Policies
	Basis of Presentation
	The accompanying consolidated financial statements include the accounts of Endocyte, Inc. and its subsidiaries and all intercompany amounts have been eliminated. The consolidated financial statements are prepared in conformity with U.S. generally accepted accounting principles (“GAAP”). Subsequent events have been evaluated through the date of issuance, which is the same as the date this Form 10-K is filed with the Securities and Exchange Commission.
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual amounts may differ from those estimates.
	Cash and Cash Equivalents
	The Company considers cash and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents consist primarily of money market instruments that are maintained by an investment manager.
	Investments
	Investments consist primarily of investments in U.S. Treasuries, U.S. Government agency obligations and corporate debt securities, which could also include commercial paper, that are maintained by an investment manager. U.S. government agency investments relate to investments in Fannie Mae, Freddie Mac and Federal Home Loan Bank. Management determines the appropriate classification of marketable securities at the time of purchase and reevaluates such classification as of each balance sheet date. Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in other comprehensive income. Realized gains and losses and declines in value judged to be other-than-temporary on available-for-sale securities are included in other income. The Company considers and accounts for other-than-temporary impairments according to the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 320, Investments — Debt and Equity Securities (“ASC 320”). The cost of securities sold is based on the specific-identification method. Discounts and premiums on debt securities are amortized to interest income and expense over the term of the security.
	Property and Equipment
	Property and equipment are stated at cost and are being depreciated using the straight-line method over estimated useful lives, which range from three to seven years.
	Licenses and Patents
	Licenses and patent costs are expensed as incurred as the Company does not believe there is an alternate future use for the costs. Licenses are classified as research and development and patents are classified as general and administrative expenses in the consolidated statements of operations.
	Long-Lived Assets
	The Company reviews long-lived assets, including property and equipment, for impairment when events or changes in business conditions indicate that their full carrying value may not be fully recoverable.
	Leases
	The Company evaluates all leases to determine whether they should be accounted for as operating or capital leases.
	Revenue Recognition
	The Company recognizes revenues from license and collaboration agreements when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the fee is fixed or determinable, and there is reasonable assurance that the related amounts are collectible in accordance with ASC Topic 605, Revenue Recognition (“ASC 605”). The Company’s license and collaboration agreements may contain multiple elements, including grants of licenses to intellectual property rights, agreement to provide research and development services and other deliverables. The deliverables under such arrangements are evaluated under ASC Subtopic 605-25, Multiple-Element Arrangements (“ASC 605-25). Under ASC 605-25, each required deliverable is evaluated to determine whether it qualifies as a separate unit of accounting based on whether the deliverable has “stand-alone value” to the customer. The arrangement’s consideration that is fixed or determinable, excluding contingent milestone payments, is then allocated to each separate unit of accounting based on the relative selling price of each deliverable. In general, the consideration allocated to each unit of accounting is recognized as the related goods or services are delivered, limited to the consideration that is not contingent upon future deliverables.
	Upfront payments for licensing the Company's intellectual property are evaluated to determine if the licensee can obtain stand-alone value from the license separate from the value of the research and development services and other deliverables in the arrangement to be provided by the Company. If at the inception of an arrangement the Company determines that the license does not have stand-alone value separate from the research and development services or other deliverables, the license, services and other deliverables are combined as one unit of account and upfront payments are recorded as deferred revenue on the balance sheet and are recognized in a manner consistent with the final deliverable. Subsequent to the inception of an arrangement, the Company evaluates the remaining deliverables for separation as items in the arrangement are delivered. When stand-alone value is identified, the related consideration is recorded as revenue in the period in which the license or other intellectual property rights are delivered.
	In those circumstances where research and development services or other deliverables are combined with the license, and multiple services are being performed such that a common output measure to determine a pattern of performance cannot be discerned, the Company recognizes amounts received on a straight line basis over the performance period. Such amounts are recorded as collaboration revenue. Any subsequent reimbursement payments, which are contingent upon the Company’s future research and development expenditures, will be recorded as collaboration revenue and will be recognized on a straight-line basis over the performance period using the cumulative catch up method. The costs associated with these activities are reflected as a component of research and development expense in the statements of operations in the period incurred. In the event of an early termination of a collaboration agreement, any deferred revenue is recognized in the period in which all obligations of the Company under the agreement have been fulfilled.
	Milestone payments under collaborative arrangements are triggered either by the results of the Company’s research and development efforts, achievement of regulatory goals or by specified sales results by a third-party collaborator. Milestones related to the Company’s development-based activities may include initiation of various phases of clinical trials and applications and acceptance for product approvals by regulatory agencies. Due to the uncertainty involved in meeting these development-based milestones, the determination is made at the inception of the collaboration agreement whether the development-based milestones are considered to be substantive (i.e. not just achieved through passage of time). In addition, the amounts of the payments assigned thereto are considered to be commensurate with the enhancement of the value of the delivered intellectual property as a result of the Company’s performance. Because the Company’s involvement is necessary to the achievement of development-based milestones, the Company would account for development-based milestones as revenue upon achievement of the substantive milestone events. Milestones related to sales-based activities may be triggered upon events such as first commercial sale of a product or when sales first achieve a defined level. Since these sales-based milestones would be achieved after the completion of the Company’s development activities, the Company would account for the sales-based milestones in the same manner as royalties, with revenue recognized upon achievement of the milestone. Royalties based on reported sales of licensed products will be recognized based on contract terms when reported sales are reliably measurable and collectability is reasonably assured. To date, none of the Company's products have been approved and therefore the Company has not earned any royalty revenue from product sales. In territories where the Company and a collaborator may share profit, the revenue would be recorded in the period earned.
	The Company often is required to make estimates regarding drug development and commercialization timelines for compounds being developed pursuant to a collaboration agreement. Because the drug development process is lengthy and the Company’s collaboration agreements typically cover activities over several years, this approach often results in the deferral of significant amounts of revenue into future periods. In addition, because of the many risks and uncertainties associated with the development of drug candidates, the Company’s estimates regarding the period of performance may change in the future. Any change in the Company’s estimates or a termination of the arrangement could result in substantial changes to the period over which the revenues are recognized.
	Research and Development Expenses
	Research and development expenses represent costs associated with the ongoing development of SMDCs and companion imaging agents and include salaries, supplies, and expenses for clinical trials. The Company records accruals for clinical trial expenses based on the estimated amount of work completed. The Company monitors patient enrollment levels and related activities to the extent possible through internal reviews, correspondence, and discussions with research organizations. In the event that a clinical trial is terminated early, the Company records, in the period of termination, an accrual for the estimated remaining costs to complete the trial.
	Upfront payments made in connection with business collaborations and research and development arrangements are evaluated under ASC Subtopic 730-20, Research and Development Arrangements. Upfront payments made in connection with business development collaborations are expensed as research and development costs, as the assets acquired do not have alternative future use. Amounts related to future research and development are capitalized as prepaid research and development and are expensed over the service period based upon the level of services provided. As of December 31, 2014, the Company had approximately $0.3 million of capitalized research and development costs included in prepaid expenses.
	Stock-Based Compensation
	The Company accounts for its stock options pursuant to ASC Topic 718, Compensation — Stock Compensation (“ASC 718”), which requires the recognition of the fair value, or calculated value for nonpublic entities, of stock-based compensation in net income. Stock-based compensation consists of stock options, which are granted at exercise prices at or above the fair market value of the Company’s common stock on the dates of grant, service-based restricted stock units (“RSUs”) and performance-based RSUs (“PRSUs”). For PRSUs issued by the Company, stock-based compensation expense will be recognized when the Company determines that it is probable that the performance conditions will be achieved. For RSUs issued by the Company, stock-based compensation expense is recognized ratably over the service period. The Company used the calculated value method to measure its stock-based compensation prior to its initial public offering on February 4, 2011. The Company recognizes compensation cost based on the grant-date fair value estimated in accordance with the provisions of ASC 718.
	Net Income (Loss) Per Share
	The Company calculates basic net income (loss) per share based on the weighted-average number of outstanding common shares. The Company calculates diluted net income (loss) per share based on the weighted-average number of outstanding common shares plus the effect of dilutive securities.
	Income Taxes
	The Company accounts for income taxes under the liability method in accordance with the provision of ASC Topic 740, Income Taxes (“ASC 740”). ASC 740 requires recognition of deferred taxes to provide for temporary differences between financial reporting and tax basis of assets and liabilities. Deferred taxes are measured using enacted tax rates expected to be in effect in a year in which the basis difference is expected to reverse. The Company continues to record a valuation allowance for the full amount of deferred tax assets, which would otherwise be recorded for tax benefits relating to operating loss and tax credit carryforwards, as realization of such deferred tax assets cannot be determined to be more likely than not.
	The Company accounts for uncertain income tax positions recognized in the financial statements in accordance with Accounting Standards Update (“ASU”) No. 2009-06. This guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return and provides guidance on derecognition of tax benefits, classification on the balance sheet, interest and penalties, accounting in interim periods, disclosure, and transition.
	Segment Information
	Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company performs clinical trials globally and has established a subsidiary in The Netherlands to assist in the administration of filing applications in Europe and a subsidiary in Switzerland for commercial pre-launch activities in Europe. The applications filed in Europe were withdrawn in May 2014 and the pre-launch activities in Europe ceased. The Company is in the process of dissolving Endocyte Europe GmbH, which should be completed in the first half of 2015. All long-lived assets are held in the U.S. The Company views its operations and manages its business in one operating segment.

New_Accounting_Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Accounting Changes and Error Corrections [Text Block]	3. New Accounting Pronouncements
	Recently Adopted Accounting Standards
	In November 2014, the FASB issued ASU No. 2014-16, Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity, an update to ASC Topic 815, Derivatives and Hedging. This amendment provides clarification regarding the “whole instrument approach” in determining the nature of a host contract in a hybrid financial instrument issued in the form of a share. Under this new standard, issuers and investors are required to consider all of a hybrid instrument’s stated and implied substantive terms and features. This update will be effective for the Company beginning January 1, 2016, unless it elects early adoption. The Company does not expect the adoption of this guidance to have a material impact on its consolidated financial statements.
	In August 2014, the FASB issued ASU 2014-15 (Subtopic 205-40), Presentation of Financial Statements — Going Concern, which requires management to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and provide related footnote disclosures. The guidance is effective for annual and interim reporting periods beginning on or after December 15, 2016. Early adoption is permitted for financial statements that have not been previously issued. The standard allows for either a full retrospective or modified retrospective transition method. This update will be effective for the Company beginning January 1, 2017, unless it elects early adoption. The Company is currently evaluating the impact, if any, the adoption of this guidance will have on its consolidated financial statements.
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606), to clarify the principles used to recognize revenue for all entities. Under the new standard, an entity should recognize revenue to depict 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 order to do so, an entity would follow the five-step process for in-scope transactions: 1) identify the contract with a customer, 2) identify the separate performance obligations in the contract, 3) determine the transaction price, 4) allocate the transaction price to the separate performance obligations in the contract, and 5) recognize revenue when (or as) the entity satisfies a performance obligation. The provisions of the new standard are effective for the Company for annual reporting periods beginning after December 15, 2016 and early adoption is not permitted. An entity can apply the new revenue standard retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the standard recognized at the date of initial application in retained earnings. The Company is currently evaluating the impact, if any, the adoption of this guidance will have on its consolidated financial statements.
	In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists, an update to ASC Topic 740, Income Taxes. This amendment provides clarification regarding the presentation of an unrecognized tax benefit related to a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. Under this new standard, the liability related to an unrecognized tax benefit, or a portion thereof, should be presented in the financial statements as a reduction to a deferred tax asset if available under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position. Otherwise, the unrecognized tax benefit should be presented in the financial statements as a separate liability. The assessment is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date. The provisions of the new standard were effective on a prospective basis beginning in 2014 for annual and interim reporting periods. This update became effective for the Company beginning January 1, 2014. The adoption did not have a material impact on the Company’s consolidated financial statements.

Net_Income_Loss_Per_Share

Net Income (Loss) Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	4. Net Income (Loss) Per Share
	Basic net income (loss) per share is calculated by dividing the net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net income (loss) per share is computed by dividing the net income (loss) attributable to common stockholders by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method and the if-converted method. For purposes of this calculation, stock options, warrants, PRSUs, RSUs and shares to be purchased under the Company’s 2010 Employee Stock Purchase Plan (“ESPP”) are considered to be common stock equivalents and are only included in the calculation of diluted net income (loss) per share when their effect is dilutive.
	As of December 31, 2012, 2013 and 2014 the following number of potential common stock equivalents were outstanding:
	Common stock equivalents
		Year Ended December 31,
		2012		2013		2014
	Outstanding common stock options		3,879,239		5,246,465		5,096,674
	Outstanding warrants		133,968		34,647		34,647
	Outstanding PRSUs		273,988		270,649		245,396
	Outstanding RSUs		—		—		161,439
	Shares to be purchased under the ESPP		—		—		2,894
	Total		4,287,195		5,551,761		5,541,050
	These common stock equivalents were excluded from the determination of diluted net loss per share for the years ended December 31, 2012 and December 31, 2013, due to their anti-dilutive effect on earnings.
	The following weighted-average outstanding common stock options, warrants, RSUs and shares to be purchased under the ESPP were added to basic weighted-average common shares outstanding for the year ended December 31, 2014 to calculate diluted weighted-average shares outstanding because of their dilutive effect:
		Year Ended
		December 31,
		2014
	Outstanding common stock options		1,494,796
	Outstanding warrants		5,433
	Outstanding RSUs		14,128
	Shares to be purchased under the ESPP		1,392
	Total		1,515,749

Other_Comprehensive_Income_Los

Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Other Comprehensive Income (Loss) [Text Block]	5. Other Comprehensive Income (Loss)
	The accumulated balances related to each component of other comprehensive income (loss) were as follows:
		Foreign			Unrealized Net			Accumulated
		Currency			Gains (Losses)			Other
		Translation			on Securities			Comprehensive
		Gains (Losses)						Gains (Losses)
	Balance at December 31, 2011	$	(5,718	)	$	(546	)	$	(6,264	)
	Unrealized gain (loss)		707			78,204			78,911
	Net amount reclassified to net loss		—			102			102
	Other comprehensive income (loss)		707			78,306			79,013
	Balance at December 31, 2012		(5,011	)		77,760			72,749
	Unrealized gain (loss)		(6,805	)		(4,203	)		(11,008	)
	Net amount reclassified to net loss		—			(5,050	)		(5,050	)
	Other comprehensive income (loss)		(6,805	)		(9,253	)		(16,058	)
	Balance at December 31, 2013		(11,816	)		68,507			56,691
	Unrealized gain (loss)		(38,776	)		(165,285	)		(204,061	)
	Net amount reclassified to net income		—			3,442			3,442
	Other comprehensive income (loss)		(38,776	)		(161,843	)		(200,619	)
	Balance at December 31, 2014	$	(50,592	)	$	(93,336	)	$	(143,928	)
	The assets and liabilities of foreign operations are translated into U.S. dollars using the current exchange rate. For those operations, changes in exchange rates generally do not affect cash flows, which results in translation adjustments being made in stockholders’ equity rather than to net income (loss).
	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
		Amount Reclassified from Accumulated									Affected Line Item in the
		Other Comprehensive Income (Loss)									Condensed Consolidated
											Statements of Operations and
	Details about Accumulated Other	Year Ended			Year Ended			Year Ended			Comprehensive Income (Loss)
	Comprehensive Income (Loss) Components	December 31,			December 31,			December 31,
		2012			2013			2014
	Unrealized Net Gains (Losses) on Securities	$	102		$	(5,050	)	$	3,442			Other income (expense)
	Total Reclassifications for the Period	$	102		$	(5,050	)	$	3,442

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	6. Investments
	The Company applies the fair value measurement and disclosure provisions of ASC Topic 820, Fair Value Measurements and Disclosures (“ASC 820”). ASC 820, which defines fair value, establishes a framework for measuring fair value in GAAP, and expands disclosures about fair value measurements. Investments consist primarily of investments with original maturities greater than three months, but no longer than 24 months when purchased.
	ASC 820 establishes a three-level valuation hierarchy for fair value measurements. These valuation techniques are based upon the transparency of inputs (observable and unobservable) to the valuation of an asset or liability as of the measurement date. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumptions. These two types of inputs create the following fair value hierarchy:
	Level 1 — Valuation is based on quoted prices for identical assets or liabilities in active markets.
	Level 2 — Valuation is based on quoted prices for similar assets or liabilities in active markets, or other inputs that are observable for the asset or liability, either directly or indirectly, for the full term of the financial instrument.
	Level 3 — Valuation is based upon other unobservable inputs that are significant to the fair value measurement.
	The fair value of the Company’s fixed income securities is based on a market approach using quoted market values.
	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2013:
	Description	Cost		Level 1		Level 2		Fair Value
								(Carrying Value)
	Cash
	Cash	$	7,887,502	$	7,887,502	$	—	$	7,887,502
	Cash equivalents
	Money market funds		44,959,438		44,959,438		—		44,959,438
	Cash and cash equivalents	$	52,846,940	$	52,846,940	$	—	$	52,846,940
	Short-term investments (due within 1 year)
	U.S. government treasury obligations	$	5,009,194	$	5,013,850	$	—	$	5,013,850
	U.S. government agency obligations		33,598,370		33,609,886		—		33,609,886
	Corporate obligations		31,789,117		—		31,810,412		31,810,412
	Total short-term investments	$	70,396,681	$	38,623,736	$	31,810,412	$	70,434,148
	Long-term investments (due after 1 year through 2 years)
	U.S. government agency obligations	$	14,807,642	$	14,821,065	$	—	$	14,821,065
	Corporate obligations		10,743,707		—		10,750,594		10,750,594
	Total long-term investments	$	25,551,349	$	14,821,065	$	10,750,594	$	25,571,659
	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2014:
	Description	Cost		Level 1		Level 2		Fair Value
								(Carrying Value)
	Cash
	Cash	$	6,068,579	$	6,068,579	$	—	$	6,068,579
	Cash equivalents
	Money market funds		39,464,864		39,464,864		—		39,464,864
	Cash and cash equivalents	$	45,533,443	$	45,533,443	$	—	$	45,533,443
	Short-term investments (due within 1 year)
	U.S. government agency obligations	$	38,934,684	$	38,928,806	$	—	$	38,928,806
	Corporate obligations		40,659,036		—		40,607,405		40,607,405
	Total short-term investments	$	79,593,720	$	38,928,806	$	40,607,405	$	79,536,211
	Long-term investments (due after 1 year through 2 years)
	U.S. government treasury obligations	$	38,626,279	$	38,623,495	$	—	$	38,623,495
	U.S. government agency obligations		35,223,450		35,203,355		—		35,203,355
	Corporate obligations		7,947,275		—		7,934,327		7,934,327
	Total long-term investments	$	81,797,004	$	73,826,850	$	7,934,327	$	81,761,177
	All securities held at December 31, 2013 and 2014, were classified as available-for-sale as defined by ASC 320.
	Total unrealized gross gains were $76,630 and $18,858 for the years ended December 31, 2013 and 2014, respectively. Total unrealized gross losses were $8,122 and $112,194 for the years ended December 31, 2013 and 2014, respectively. The Company does not consider any of the unrealized losses to be other-than-temporary impairments because the Company has the intent and ability to hold investments until they recover in value. Total realized gross gains were $11,342 and $1,429 for the years ended December 31, 2013 and 2014, respectively. There were no total realized gross losses for the years ended December 31, 2013 or 2014.

Property_and_Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	7. Property and Equipment
	Property and equipment consisted of the following:
		Estimated		December 31,
		Useful Lives		2013			2014
	Laboratory equipment		7	$	4,796,393		$	5,828,045
	Office equipment and software		3 – 7		972,789			1,225,298
	Leasehold improvements		7		348,901			400,018
	Assets not in service				503,208			23,836
					6,621,291			7,477,197
	Less accumulated depreciation				(2,781,865	)		(3,506,532	)
				$	3,839,426		$	3,970,665
	Assets not in service represent new laboratory and computer equipment that was not installed and ready to use at December 31, 2013 and 2014. The total amount of depreciation expense for the years ended December 31, 2012, 2013 and 2014 were $358,367, $674,725 and $857,055, respectively.

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	8. Long-Term Debt
	In August, 2010 the Company obtained a $15.0 million loan commitment from Mid Cap Financial (“Mid-Cap”) and Silicon Valley Bank (“SVB”) and borrowed $10.0 million at the time the facility was created. In December 2010, the Company accessed the remaining tranche of $5.0 million. In June 2012, the company terminated the facility, paid the entire outstanding balance and recorded a loss on debt extinguishment of $992,000, which included a 5% prepayment fee of $615,000 and the write off of unamortized deferred financing fees and discounts of $377,000. In connection with the loan during 2010, the Company issued warrants to lenders to purchase an aggregate of 64,674 shares of Series C-3 convertible preferred stock. The fair value of the preferred stock warrants issued was $219,322 on the dates of issuance and was based on observable inputs using quoted market values and the income approach as derived by the Black-Scholes model. The terms of these preferred stock warrants are described in Note 9.
	Interest paid was $655,834, $0 and $0 for the years ended December 31, 2012, 2013 and 2014, respectively.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Preferred Stock [Text Block]	9. Warrants
	In 2007, the Company issued warrants as consideration in connection with its loan commitment from General Electric Capital Corporation and Oxford Finance Corporation (“Oxford”) to purchase 69,294 of Series C-3 convertible preferred stock, maturing in 2017. These preferred stock warrants were exercisable upon issuance, and no contingent conversion feature exists. Upon closing of the initial public offering, these warrants were converted to warrants to purchase common stock and were reclassified to stockholders’ equity.
	In August 2010 and December 2010, the Company issued warrants as consideration in connection with its loan commitment from Mid-Cap and SVB to purchase either Series C-3 preferred stock or preferred stock offered in a subsequent offering. The number of preferred stock warrants issued was based on the Series C-3 convertible preferred stock and an $8.12 per share exercise price. The preferred stock warrants would have matured in 2020, were exercisable upon issuance and did not contain contingent conversion features. Upon closing of the initial public offering, these warrants were converted to warrants to purchase common stock and were reclassified to stockholders’ equity.
	During 2013, the Company issued 47,791 shares of common stock in connection with the cashless exercise of warrants to purchase stock. As a result, the warrants issued to Oxford, Mid-Cap and SVB were no longer outstanding as of December 31, 2013.

Leases

Leases	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Leases of Lessee Disclosure [Text Block]	10. Leases
	Future minimum lease payments for noncancellable operating leases as of December 31, 2014, are as follows:
	2015	$	731,555
	2016		154,663
	2017		158,474
	2018		26,677
	2019		—
	Thereafter		—
	Total minimum lease payments	$	1,071,369
	Rent expense for operating leases was $512,855, $784,531 and $866,768 for the years ended December 31, 2012, 2013 and 2014, respectively.

Stockholders_Equity_Deficit

Stockholders' Equity (Deficit)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	11. Stockholders’ Equity (Deficit)
	Stock-Based Compensation Plans
	The Company has had stock-based compensation plans since 1997. The awards made under the plans adopted in 1997 and 2007 consisted of stock options. The 2010 Equity Incentive Plan (the “2010 Plan”), which is the only plan under which awards may currently be made, authorizes awards in the form of stock options, stock appreciation rights, restricted stock, PRSUs, performance units and performance shares, and RSUs. Awards under the 2010 Plan may be made to employees, directors and certain consultants as determined by the compensation committee of the board of directors. There were 6,625,563 and 8,071,563 shares of common stock authorized and reserved under these plans at December 31, 2013 and December 31, 2014, respectively.
	Stock Options
	Under the various plans, employees have been granted incentive stock options, while directors and consultants have been granted non-qualified options. The plans allow the holder of an option to purchase common stock at the exercise price, which was at or above the fair value of the Company’s common stock on the date of grant.
	Generally, options granted under the 1997 and 2007 plans in connection with an employee’s commencement of employment vest over a four-year period with one-half of the shares subject to the grant vesting after two years of employment and remaining options vesting monthly over the remainder of the four-year period. Options granted under the 1997 and 2007 plans for performance or promotions vest monthly over a four-year period. Generally, options granted under the 2010 Plan vest annually over a four-year period. Unexercised stock options terminate on the tenth anniversary date after the date of grant. The Company recognizes stock-based compensation expense over the requisite service period of the individual grantees, which generally equals the vesting period. The Company utilizes a Black-Scholes option-pricing model to estimate the value of stock options. The Black-Scholes model allows the use of a range of assumptions related to volatility, risk-free interest rate, employee exercise behavior and dividend yield. Prior to 2013, since the Company did not have sufficient history as a publicly traded company to evaluate volatility, the Company used an average of several peer companies’ volatilities to determine a reasonable estimate of volatility. Beginning in 2013, the Company utilizes a combination of peer volatility and company volatility. For purposes of identifying peer companies, the Company considered characteristics such as industry, length of trading history, market capitalization and similar product pipelines.
	Due to insufficient history as a public company, the Company is using the “simplified” method for “plain vanilla” options to estimate the expected term of the stock options grants. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option. The risk-free interest rate assumption is derived from the weighted-average yield of a U.S. Treasury security with the same term as the expected life of the options, and the dividend yield assumption is based on historical experience and the Company’s estimate of future dividend yields.
	The weighted-average value of the individual options granted during 2012, 2013 and 2014 were determined using the following assumptions:
		Year Ended December 31,
		2012			2013			2014
	Weighted-average volatility		89.13	%		101	%		102.86	%
	Risk-free interest rate		1.1	%		1.31	%		1.98	%
	Weighted-average expected life (in years)		6.2			6.6			6.6
	Dividend yield		0	%		0	%		0	%
	The resulting value of options granted was $13,725,956 and $9,188,595 for the years ended December 31, 2013 and 2014, respectively, which will be amortized into income over the remaining requisite service period. The Company recognized stock-based compensation cost, net of forfeitures, in the amount of $3,022,693, $6,059,005 and $8,025,261 for the years ended December 31, 2012, 2013 and 2014, respectively. The Company’s stock option activity and related information are summarized as follows:
		Options			Weighted-Average			Weighted-Average			Aggregate
					Exercise Price			Remaining			Intrinsic Value
								Contractual Term
								(In Years)
	Outstanding at January 1, 2012		2,592,009		$	5.12
	Granted during year		1,492,395			4.61
	Exercised during year		(134,534	)		2.91
	Expired during year		(13,502	)		9.86
	Forfeited during year		(57,129	)		6.68
	Outstanding at December 31, 2012		3,879,239		$	4.96			7.5		$	16,198,044
	Exercisable at December 31, 2012		1,676,016			3.83			5.72			8,882,339
	Outstanding at January 1, 2013		3,879,239			4.96
	Granted during year		1,566,062			10.79
	Exercised during year		(188,699	)		3.42
	Expired during year		—			—
	Forfeited during year		(10,137	)		6.04
	Outstanding at December 31, 2013		5,246,465		$	6.76			7.39		$	22,002,357
	Exercisable at December 31, 2013		2,269,438			4.59			5.73			13,968,005
	Outstanding at January 1, 2014		5,246,465			6.76
	Granted during year		1,065,386			10.54
	Exercised during year		(399,654	)		3.23
	Expired during year		(244,121	)		9.17
	Forfeited during year		(571,402	)		10.49
	Outstanding at December 31, 2014		5,096,674		$	7.29			6.87		$	6,329,518
	Exercisable at December 31, 2014		2,695,278			5.89			5.68			4,986,059
	The following is a rollforward of the Company’s nonvested stock options from January 1, 2012 to December 31, 2014.
		Options			Weighted-Average
					Grant Date Value
	Nonvested stock options at January 1, 2012		1,252,668		$	5.34
	Granted during year		1,492,395			3.42
	Vested during year		(484,711	)		4.51
	Expired during year		—			—
	Forfeited during year		(57,129	)		4.61
	Nonvested at December 31, 2012		2,203,223		$	4.24
	Nonvested stock options at January 1, 2013		2,203,223		$	4.24
	Granted during year		1,566,062			8.76
	Vested during year		(782,121	)		4.22
	Expired during year		—			—
	Forfeited during year		(10,137	)		4.58
	Nonvested at December 31, 2013		2,977,027		$	6.62
	Nonvested stock options at January 1, 2014		2,977,027		$	6.62
	Granted during year		1,065,386			8.62
	Vested during year		(1,069,615	)		6.61
	Expired during year		—			—
	Forfeited during year		(571,402	)		8.36
	Nonvested at December 31, 2014		2,401,396		$	7.07
	The total grant date value of stock options vested during 2012, 2013 and 2014 was $2,216,038, $3,303,701 and $7,072,923 respectively. As of December 31, 2013 and December 31, 2014, the total remaining unrecognized compensation cost, net of forfeitures, related to stock options granted was $13,900,183 and $11,092,519, respectively, which is expected to be recognized over weighted average periods of approximately 1.8 and 1.6 years, respectively. The intrinsic value of options exercised was $1,884,651 and $2,934,244 for the years ended December 31, 2013 and December 31, 2014, respectively.
	Restricted Stock Units
	In May 2011, the Company adopted and granted awards under a performance-based RSU program (the “2011 PRSU Program”) under the 2010 Plan. Each unit represents an amount equal to one share of the Company’s common stock. The PRSUs will be earned, in whole or in part, based on performance and service conditions. The performance condition is based upon whether the Company receives regulatory approval to sell a therapeutic product, and the awards include a target number of PRSUs that will vest upon a First Commercial Approval, and a maximum number of PRSUs that will vest upon a Second Commercial Approval. Any earned PRSUs will vest fifty percent based on the performance condition of commercial approval and fifty percent one year thereafter to fulfill the service condition, which requires the employee to remain employed by the Company.
As of December 31, 2014, the Company had 245,396 PRSU awards outstanding. The unrecorded stock compensation expense is based on number of units granted, less estimated forfeitures based on the Company’s historical forfeiture rate of 6.49%, and the closing market price of the Company’s common stock at the grant date. As of December 31, 2014, the performance condition of obtaining regulatory approval had not been achieved, therefore, no vesting had occurred. The awards are being accounted for under ASC 718, and compensation expense is to be recorded if the Company determines that it is probable that the performance conditions will be achieved. As of December 31, 2014, it was not probable that the performance conditions will be achieved, therefore, no compensation expense related to the PRSUs was recorded for the
year ended December 31, 2014. Unrecorded compensation expense for the 2011 PRSU program as of December 31, 2014 was $2.7 million. Based on the performance conditions and the stage of development of our potential products, we have concluded that the performance conditions will not be achieved before the performance deadline and, as a result, we do not expect to recognize any stock-based compensation expense related to the PRSUs.
As of December 31, 2014, the Company had 161,439 RSU awards outstanding under the 2010 Plan which were granted in February 2014. The RSUs are service-based awards that will vest and be paid in four equal installments annually beginning in February 2015 in the form of one share of the Company’s common stock for each RSU. The awards were granted at a weighted average fair value of $11.11 per share, calculated using the closing stock price of a share of our common stock on the grant date, net of forfeitures, over the life of the vesting period. As of December 31, 2014, the total remaining unrecognized compensation cost, net of forfeitures, related to RSUs was $1.3 million, which is expected to be recognized over a weighted average period of approximately 2.0 years.
Employee Stock Purchase Plan
Effective January 1, 2014, the Company implemented the ESPP. At January 1, 2014, 622,780 common shares were available for issuance under the ESPP. Shares may be issued under the ESPP twice a year. In the year ended December 31, 2014, plan participants purchased 53,250 shares of common stock under the ESPP at an average purchase price of $5.62 per share. At December 31, 2014, 569,530 shares were available for issuance under the ESPP.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	12. Income Taxes
	A reconciliation of the expected income tax benefit (expense) computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2012, 2013, and 2014:
		December 31,
		2012				2013			2014
	Income tax computed at federal statutory tax rate		34	%			34	%		34	%
	State taxes, net of federal benefit		3.9	%			4.2	%		6.3	%
	State taxes rate change, net of federal benefit		—				—			30.4	%
	International operations		-0.2	%			-2.1	%		6.6	%
	Research and development credits		2.4	%			13.8	%		-22.6	%
	Orphan drug credits		—				6.6	%		-57.4	%
	Equity compensation		-2.2	%			-2.5	%		16.6	%
	Other		-0.2	%			-1.3	%		-2.1	%
	Change in valuation allowance		-37.7	%			-52.7	%		-11.8	%
	Total		0	%			0	%		0	%
	At December 31, 2014, the Company had net operating loss carryforwards totaling approximately $179,478,000 and $235,422,000 for federal and state income taxes, respectively, that may be used to offset future taxable income. If not used, the carryforwards will begin expiring in the year 2021. The Company has determined that it experienced a change in ownership as defined under Section 382 of the U.S. Internal Revenue Code (the “Code”), as a result of the public offering in August 2011. As a result, the future use of its net operating losses, after giving effect to net unrealized built-in gains, will be limited to approximately $133,200,000 for 2014, $39,000,000 for 2015, $29,700,000 for 2016 and $16,800,000 for 2017. Any available but unused amounts will become available for use in all successive years.
	Net deferred tax assets and liabilities are comprised of the following:
		December 31,
		2013			2014
	Deferred tax assets
	Net operating loss carryforwards	$	65,678,000		$	71,074,000
	Research and development credit carryforwards		9,592,000			10,836,000
	Orphan Drug Credit		1,495,000			6,286,000
	Stock options		2,377,000			4,103,000
	Other		120,000			202,000
	Deferred tax assets		79,262,000			92,501,000
	Deferred tax liabilities
	Deferred revenue		-2,594,000			-16,408,000
	Property and equipment		-241,000			-316,000
	Deferred tax liabilities	$	-2,835,000		$	-16,724,000
	Net deferred tax asset before valuation allowance	$	76,427,000		$	75,777,000
	Less valuation allowance		-76,427,000			-75,777,000
	Net deferred tax assets	$	—		$	—

Collaborations

Collaborations	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative Arrangement Disclosure [Text Block]	13. Collaborations
	In October 2007, the Company entered into an exclusive worldwide license with R&D Biopharmaceuticals to research, develop, and commercialize products containing conjugates of folate receptor targeting compounds and tubulysin compounds. In February 2011, this licensing agreement was assigned by R&D Biopharmaceuticals to Trientlgasse. The Company paid an upfront fee of $300,000 as research and development and pays $25,000 in annual maintenance fees unless a milestone is paid in a given year. In 2013, the Company paid $100,000 for dosing the first human patient with folate tubulysin. In 2014, the Company paid $50,000 for the completion of toxicology studies in compliance with Good Laboratory Practice and $100,000 for dosing the first human patient with PSMA tubulysin. The Company could pay $5,900,000 in additional contingent payments upon the achievement of specific scientific, clinical, and regulatory milestones, in addition to royalties upon commercial sales. All payments have been expensed as research and development as incurred, as there is no alternate future use for this technology.
	In December 1995, as amended in October 1998, the Company entered into an exclusive license agreement with Purdue Research Foundation, which licenses the right under certain patents to the Company. The Company is obligated to pay an annual minimum royalty of $12,500 until commercial sales commence, following which time the payment of single digit royalty rates will commence. All payments have been expensed as incurred. The Company does not anticipate incurring any liabilities for vintafolide royalty payments based on the estimate timing of when commercial sales may commence and the expiration of the applicable patents.
	In December 2009, the Company entered into a financial term sheet to be incorporated into a written license agreement with Purdue Research Foundation for a patent related to prostate cancer. The agreement was signed and became effective on March 1, 2010. Pursuant to the exclusive license agreement, the Company is subject to minimum annual royalty payments of $15,000, payable until first commercial sale, following which time the minimum annual royalty payments increase to $100,000 and sales-based royalties are also payable at market rates when commercial sales commence. In addition, a milestone payment of $500,000 is payable upon approval of a new drug application in the U.S. In 2014, the Company paid a penalty as a milestone was not met. The Company is subject to future penalties if certain diligence milestones are not met.
	In 2014, the Company entered into a Master License Agreement with Purdue Research Foundation. Under this license, the Company has the right to exclusively license patents and technology discovered under company funded research at Purdue University. If the Company decides to move forward with development of one or more of these technologies, the Company will be obligated to make an acceptance payment and the Company will also be obligated to make contingent payments upon the achievement of specific scientific, clinical and regulatory milestones. Certain scientific, clinical and regulatory milestones, in addition to internal resource targets must be met by the Company to avoid fees as consideration for waivers of potentially missed milestones. The Company is obligated to pay annual minimum payments until commercial sales commence, following which time the payments of royalties with market rates will commence, along with an annual royalty payment per annum.
	Merck Collaboration Agreement
	In April 2012, the Company entered into a worldwide collaboration agreement with Merck Sharp & Dohme Research GmbH, a subsidiary of Merck & Co, Inc. (“Merck”), regarding the development and commercialization of vintafolide, which agreement was terminated by Merck effective September 15, 2014. As a result of the termination of the collaboration with Merck, the Company is no longer eligible for additional milestone payments from Merck. In addition, all obligations of the Company under the agreement have been fulfilled and the Company is not required to perform any additional services to Merck. Pursuant to the collaboration agreement, the Company received a $120.0 million non-refundable upfront payment and a $5.0 million milestone payment in 2012. Under the collaboration agreement, the Company was responsible for the majority of funding and completion of the Phase 3 PROCEED clinical trial of vintafolide for the treatment of patients with platinum-resistant ovarian cancer (“PROC”), which was terminated in May 2014. The Company is responsible for the execution of the Phase 2b TARGET trial of vintafolide for the treatment of second line non-small cell lung cancer, which is now substantially complete, pending the receipt of final overall survival results. Merck was responsible for the costs of the TARGET trial through September 15, 2014.
	For revenue recognition purposes, the Company viewed the collaboration with Merck as a multiple element arrangement. Multiple element arrangements are analyzed to determine whether the various performance obligations, or elements, can be separated or whether they must be accounted for as a single unit of accounting. The Company evaluated whether the delivered elements under the arrangement have value on a stand-alone basis and whether objective and reliable evidence of fair value of the undelivered element exists. Deliverables that do not meet these criteria are not evaluated separately for the purpose of revenue recognition. For a single unit of accounting, payments received are recognized in a manner consistent with the final deliverable. The Company determined that the deliverables related to the collaboration with Merck, including the licenses granted to Merck, as well as the Company performance obligations to provide various research and development services, would be accounted for as a single unit of account. This determination was made because the successful development of the therapeutic drug, vintafolide, is dependent on the companion diagnostic, etarfolatide, to select patients who are most likely to receive the most benefit from vintafolide. Given the nature of the combined benefit of the companion diagnostic and the therapeutic drug, the research and development services to be provided by the Company were essential to the overall arrangement as the Company has significant knowledge and technical know-how that was important to realizing the value of the licenses granted. Subsequent to the inception of the Merck arrangement, the Company evaluated the remaining deliverables for separation as items in the arrangement were delivered.
	The Company recognized the non-refundable $120.0 million upfront payment, the $5.0 million milestone payment and funding from the research and development services on a straight-line basis over the estimated performance period, which started at the date of execution of the agreement. Based on the termination of the PROCEED trial and receiving the notice of termination of the collaboration agreement in 2014, the Company concluded that all of its obligations under the agreement have been fulfilled and the Company is not required to perform any additional services to Merck, and as a result, the entire balance of deferred revenue related to the collaboration agreement was recognized in 2014. The Company recognized approximately $64.9 million and $70.3 million of revenue related to the Merck collaboration during 2013 and 2014, respectively, and had deferred revenue related to the collaboration of approximately $59.7 million at December 31, 2013. There was no deferred revenue related to the collaboration at December 31, 2014. Though accounted for as a single unit of account for presentation purposes, the Company made an allocation of revenue recognized as collaboration revenue between the license and the services. This allocation was based upon the relative selling price of each deliverable. For the years ended December 31, 2013 and 2014, license revenue was approximately $51.5 million and $52.7 million, respectively, while research and development services revenue was approximately $13.4 million and $17.6 million, respectively, of the collaboration revenue.
	In 2014, Merck and the Company entered into a letter agreement whereby Merck agreed to pay (i) $2.2 million of expenses related to costs incurred to prepare for the potential increase in the number of FR(100%) patients (patients in which 100 percent of their target lesions over-expressed the folate receptor as determined by an etarfolatide scan) in the PROCEED trial from 250 to 350, for which Merck agreed to reimburse at 75%, and (ii) $1.1 million related to the remaining PROCEED trial expenses beyond the September 15, 2014 termination date. The Company has no obligations nor is it required to perform any additional services under that letter agreement. Revenue for these additional payments was recognized in 2014.
	In 2014, Merck and the Company entered into a second letter agreement whereby Merck agreed to pay $0.5 million related to the estimate of reimbursable development expenses incurred but not yet invoiced to Merck. Under that letter agreement, Merck and the Company agreed that there will be no additional amounts payable by either party if the actual expenses differ from the estimated expenses paid by Merck.
	NMP License and Commercialization Agreement
	In August 2013, the Company entered into a license and commercialization agreement with Nihon Medi-Physic Co., LTD. (“NMP”) that grants NMP the right to develop and commercialize etarfolatide in Japan for use in connection with vintafolide in Japan. The Company received a $1.0 million non-refundable upfront payment, is eligible for up to $4.5 million based on the successful achievement of regulatory goals for etarfolatide in five different cancer indications and is eligible to receive double-digit percentage royalties on sales of etarfolatide in Japan.
	For revenue recognition purposes, the Company viewed the agreement with NMP as a multiple element arrangement. Multiple element arrangements are analyzed to determine whether the various performance obligations, or elements, can be separated or whether they must be accounted for as a single unit of accounting. The Company has identified the deliverables related to the collaboration with NMP, which include the license granted to NMP, as well as the obligation to provide preclinical and clinical supply of etarfolatide, to provide rights to NMP if a product is developed that replaces etarfolatide, obligation for the Company to provide clinical data to NMP during the contract period and coordination of development and commercialization efforts between the Company for vintafolide and NMP for etarfolatide in Japan. The Company’s deliverables will be accounted for as a single unit of account, therefore the non-refundable upfront payment is being recognized on a straight-line basis over the performance period. This determination was made because the successful development of etarfolatide in Japan requires the ongoing participation by the Company, including the development of the related therapeutic drug, vintafolide. The performance period over which the revenue will be recognized continues from the date of execution of the agreement through the end of 2033, the estimated termination date of the contract which is when the Company’s performance obligations will be completed. Any significant changes in the timing of the performance period could result in a change in the revenue recognition period. The Company had deferred revenue related to the agreement of approximately $0.9 million at December 31, 2014. Subsequent to the inception of the NMP arrangement, the Company evaluates the remaining deliverables for separation as items in the arrangement are delivered.
	The arrangement with NMP includes milestone payments of up to approximately $4.5 million and the milestones are based on the commencement of clinical trials in Japan for specific and non-specific indications and filing for approval in Japan for specific and non-specific indications. The Company evaluated each of these milestone payments and believes that all of the milestones are substantive as there is substantial performance risk that must occur in order for them to be met because the Company must complete additional clinical trials which show a positive outcome or receive approval from a regulatory authority and would be commensurate with the enhancement of value of the underlying intellectual property. To date, the products have not been approved in Japan and no revenue has been recognized related to the regulatory milestones or royalties.
	NMP has the right to terminate the collaboration agreement on 90 days notice prior to first commercial sale in Japan and six months notice after the first commercial sale in Japan. NMP also has the right to terminate the agreement on six months notice if the Company fails to launch vintafolide after receiving regulatory approval in Japan. NMP and the Company each have the right to terminate the agreement due to the material breach or insolvency of the other party. Upon termination of the agreement depending on the circumstances, the parties have varying rights and obligations with respect to licensing and related regulatory materials and data.

RelatedParty_Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	14. Related-Party Transactions
	The Company funds research at Purdue University, the employer of one of its founders and current Chief Science Officer. Amounts included in research and development expenses were $788,737, $824,559 and $1,000,000 for the years ended December 31, 2012, 2013 and 2014, respectively.
	In September 2011, the Company entered into exclusive worldwide licenses with On Target Laboratories, L.L.C. (“On Target”) to develop and commercialize products relating to the compound comprising the Company’s Folate and DUPA ligands and other certain Licensed Patents. On Target’s Chief Executive Officer is the brother of the Company’s Chief Science Officer. The Company believes that the terms of the agreement are no less favorable than terms that would have been available in an arm’s length transaction. On Target is solely responsible for conducting research and development, seeking regulatory approval and commercialization of products. The Company received nonrefundable upfront license fees totaling $191,000 from On Target in December 2011. The Company has determined that the deliverables under this agreement do not meet the criteria required for separate accounting units for the purposes of revenue recognition, and as a result, the Company recognized revenue from non-refundable, upfront fees when the performance condition of delivering the licenses and certain consultation services had been achieved and there was reasonable assurance of collectability. If On Target fails to meet minimum spend requirements on research and development, the Company has the right to terminate the agreement. The Company will be entitled to receive minimum royalty payments annually based on net sales, but there is no guarantee that a commercial product will be developed and approved for commercial sales. The Company will also be entitled to reimbursement of expenses relating to patent expenses and payments to the inventors and Purdue University if certain milestones are met. During 2011, the Company received a $50,000 reimbursement from On Target for payments made to inventors for issued patents. The Company received $20,000 in annual maintenance license fees during each of 2013 and 2014, and received $27,394 and $50,614 for reimbursable research and development expenses, for 2013 and 2014, respectively.

Retirement_Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]	15. Retirement Plans
	The Company maintains a 401(k) retirement savings plan to provide retirement benefits for substantially all of its employees. Participants in the plan may elect to contribute a portion of their annual compensation to the plan, limited to the maximum allowed by the Code. Prior to January 1, 2014 the Company did not match 401(k) contributions. Effective January 1, 2014, the Company implemented a matching contribution for the 401k contributions. For the year ended December 31, 2014, the Company had approximately $0.3 million of expense related to the 401(k) employer match.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	16. Commitments and Contingencies
	On June 24, 2014, a complaint in a securities class action lawsuit was filed against the Company and one of its officers and directors in the United States District Court for the Southern District of Indiana under the following caption: Tony Nguyen, on Behalf of Himself and All Others Similarly Situated v. Endocyte, Inc. and P. Ron Ellis (the “Nguyen Litigation”). On July 13, 2014, a nearly identical complaint in a securities class action lawsuit was filed against the Company and one of its officers and directors in the United States District Court for the Southern District of Indiana under the following caption: Vivian Oh Revocable Trust, Individually and on Behalf of All Others Similarly Situated v. Endocyte, Inc. and P. Ron Ellis (the “Oh Litigation”). On September 22, 2014, the court named a lead plaintiff (“Lead Plaintiff”) and consolidated the Nguyen Litigation and the Oh Litigation under the following caption: Gopichand Vallabhaneni v. Endocyte, Inc. and P. Ron Ellis (the “Vallabhaneni Litigation”). On November 17, 2014, Lead Plaintiff filed a consolidated amended securities class action complaint (the “Amended Complaint”) against the Company, P. Ron Ellis, Beth Taylor, Michael A. Sherman, John C. Aplin, Philip S. Low, Keith A. Brauer, Ann F. Hanham, Marc Kozin, Peter D. Meldrum, Fred A. Middleton, Lesley Russell (the “Individual Defendants” and collectively with the Company, the “Endocyte Defendants”), and Credit Suisse Securities (USA) LLC and Citigroup Global Markets Inc. (the “Underwriter Defendants”). Lead Plaintiff alleged, among other things, that the Endocyte Defendants made false and misleading statements relating to the efficacy of vintafolide and violated Sections 10(b) and 20(a) of the Exchange Act. The putative class related to these allegations consists of all persons who purchased or otherwise acquired the Company’s securities between March 21, 2014 and May 2, 2014. Lead Plaintiff also alleged in the Amended Complaint that the Endocyte Defendants and the Underwriter Defendants violated Sections 11 and 15 of the Securities Act of 1933, as amended (the “Securities Act”), by, among other things, making or allowing the Company to make false and misleading statements regarding positive opinions about vintafolide issued by the European Medicines Agency’s Committee for Medicinal Products for Human Use in the Company’s Registration Statement on Form S-3 filed on March 25, 2014, preliminary prospectus filed on March 26, 2014, and final prospectus filed on March 28, 2014. The putative class related to these allegations consists of all those who purchased or otherwise acquired the Company’s securities pursuant to or traceable to the Company’s April 2, 2014 public offering.
	Lead Plaintiff seeks the designation of the Vallabhaneni Litigation as a class action, an award of unspecified damages, interest, costs, expert fees and attorneys’ fees, and equitable/injunctive relief or other relief as the court may deem just and proper. Pursuant to a December 9, 2014 order, all Defendants filed a motion to dismiss on March 6, 2015. Discovery in this matter is stayed pursuant to provisions of the Private Securities Litigation Reform Act (“PSLRA”) pending resolution of that motion to dismiss. The Company believes that this lawsuit is without merit and has defended, and intends to continue to defend, itself vigorously against the allegations made in the Amended Complaint.
	On September 23, 2014, a complaint in a shareholder derivative lawsuit was filed against all of the Company’s current directors in the United States District Court for the Southern District of Indiana under the following caption: William Moore, Derivatively on Behalf of Nominal Defendant Endocyte, Inc. v. John C. Aplin, et al. (the “Moore Litigation”). The Company was named as a nominal defendant in the case. The complaint alleged, among other things, that the defendants violated state law, including through breaches of fiduciary duties, gross mismanagement, waste of corporate assets and unjust enrichment, in regard to false and misleading statements and material omissions made concerning the efficacy of vintafolide, causing substantial monetary losses to the Company and other damages, including irreparable damages to the Company’s reputation and goodwill. The complaint sought: unspecified damages from each of the defendants, jointly and severally, together with interest thereon; an order directing that actions be taken to reform and improve the Company’s corporate governance and internal procedures to comply with applicable laws and to protect the Company’s shareholders from a repeat of the alleged damaging events; an award of unspecified exemplary damages; restitution; costs and disbursements, including reasonable attorneys’ and experts’ fees, costs and expenses; and such other and further equitable relief as the court may deem just and proper.
	On October 31, 2014, a complaint in a shareholder derivative lawsuit nearly identical to the Moore Litigation was filed against all of the Company’s current directors in the United States District Court for the Southern District of Indiana under the following caption: Victor Veloso, Derivatively on Behalf of Endocyte, Inc. v. John C. Aplin, et al. (the “Veloso Litigation”). The Company was named as a nominal defendant in the case. The complaint alleged, among other things, that the defendants violated and breached their fiduciary duties of care, loyalty, reasonable inquiry and good faith by causing the Company to issue false and misleading statements concerning its financial condition, resulting in significant damages, not only monetarily, but also to its corporate image and goodwill, including costs associated with defending securities lawsuits, severe damage to its share price, resulting in an increased cost of capital, the waste of corporate assets and reputational harm. The complaint sought: unspecified damages from all of the defendants; an order directing that the Company take all necessary actions to reform and improve its corporate governance and internal procedures, to comply with existing governance obligations and all applicable laws and to protect the Company and its investors from a recurrence of the alleged damaging events; costs and disbursements, including reasonable attorneys’ fees, accountants’ and experts’ fees, costs and expenses; and such other and further relief as the court deems just and proper.
	On December 31, 2014, the court appointed co-lead counsel and consolidated the Moore Litigation with the Veloso Litigation under the following caption: In re Endocyte, Inc. Derivative Litigation (the “Endocyte Derivative Litigation”). An amended complaint was filed on February 28, 2015 which contains allegations and requests for relief that are substantially the same as the complaints in the Moore Litigation and the Veloso Litigation. Although this lawsuit is brought nominally on behalf of the Company, the Company expects to incur defense costs and other expenses in connection with the lawsuit. Discovery and other proceedings in this matter are currently stayed pursuant to agreement of the parties pending resolution of the March 6, 2015 motion to dismiss in the Vallabhaneni Litigation.
	On November 6, 2014, a complaint was filed against the Company, two of its executive officers, Merck and one of Merck’s officers in the Superior Court of Tippecanoe County, Indiana under the following caption: Mohamad Hage and Jamele Hage v. Endocyte, Inc., P. Ron Ellis, Mike A. Sherman, Eric Rubin and Merck & Co., Inc. (the “Hage Litigation”). The complaint alleged, among other things, that the defendants: made false and misleading statements about the efficacy of vintafolide and the likelihood that it would be approved for sale; employed devices, schemes and artifices to defraud; made untrue statements of material facts and omitted to state material facts necessary in order to make the statements made about the Company and its business operations not misleading; and breached fiduciary duties owed to the plaintiffs. The complaint alleged that as a result of the alleged fraudulent misrepresentations, non-disclosures and schemes of the defendants, plaintiffs have suffered pecuniary losses. The plaintiffs seek an award of unspecified actual, compensatory, consequential, incidental and punitive damages, reasonable costs, expert fees and attorneys’ fees, and such equitable/injunctive or other relief as the court may deem just and proper. The Company believes that it may have an obligation to indemnify Merck and its named officer in connection with the Hage Litigation, depending on certain factors. On January 9, 2015, the defendants filed a Motion to Stay the Proceeding or in the Alternative to Stay Discovery (the “Motion to Stay”). A hearing on the Motion to Stay was held on February 19, 2015 and the parties are waiting for the court to rule. The Company believes that this lawsuit is without merit and has defended, and intends to continue to defend, itself vigorously against the allegations made in the complaint.
	The Company also has certain obligations to indemnify, and advance expenses to, its directors and officers in connection with various actions, suits and proceedings.

Restructuring_Costs

Restructuring Costs	12 Months Ended
	Dec. 31, 2014
Restructuring Costs [Abstract]
Restructuring and Related Activities Disclosure [Text Block]	17. Restructuring Costs
	The Company terminated the PROCEED trial in May 2014 after the interim futility analysis indicated that vintafolide did not demonstrate efficacy on the pre-specified outcome of progression-free survival for the treatment of PROC. As a result, the Company ceased its pre-launch commercial activities and implemented staff reductions in Europe and in the U.S. Included in general and administrative expenses for the year ended December 31, 2014, were expenses for employee termination benefits and contract termination costs of $1.3 million, and included in research and development expenses were $4.1 million of expenses for the PROCEED trial, including continued patient therapy costs for the patients who chose to stay on treatment, as well as site close-out expenses. As of December 31, 2014, all severance had been paid, and the Company had a clinical trial accrual balance related to the PROCEED trial termination of $1.3 million, which is expected to be fully paid by June 2015.
	The following table summarizes the restructuring accruals for the year ended December 31, 2014:
		Employee and			PROCEED			Total
		Contract			Trial
		Termination			Termination
		Accrual			Accrual
	Balance, January 1, 2014	$	—		$	—		$	—
	Charges for the year ended December 31, 2014		1,300,000			4,100,000			5,400,000
	Amounts paid in the year ended December 31, 2014		(1,300,000	)		(2,800,000	)		(4,100,000	)
	Balance, December 31, 2014	$	—		$	1,300,000		$	1,300,000

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	18. Selected Quarterly Financial Data (unaudited)
	The following table summarizes the unaudited statements of operations for each quarter of 2014 and 2013 (in thousands except share and per share amounts):
			Quarters Ended
			31-Mar			30-Jun			30-Sep			31-Dec
	2014
	Revenue		$	17,269		$	49,168		$	3,904		$	12
	Operating Expenses:
	Research and development			12,987			18,990			5,675			3,998
	General and administrative			7,501			7,968			4,007			4,201
	Income (loss) from operations			(3,219	)		22,210			(5,778	)		(8,187	)
	Interest, net			85			168			161			164
	Other			(7	)		(22	)		(58	)		(58	)
	Net income (loss)		$	(3,141	)	$	22,356		$	(5,675	)	$	(8,081	)
	Basic net income (loss) per share(1)		$	(0.09	)	$	0.54		$	(0.14	)	$	(0.19	)
	Diluted net income (loss) per share(1)		$	(0.09	)	$	0.52		$	(0.14	)	$	(0.19	)
	Weighted average common shares outstanding – basic			36,193,942			41,398,251			41,564,840			41,736,930
	Weighted average common shares outstanding – diluted			36,193,942			43,196,754			41,564,840			41,736,930
			Quarters Ended
			31-Mar			30-Jun			30-Sep			31-Dec
	2013
	Revenue		$	14,514		$	16,483		$	16,600		$	17,274
	Operating Expenses:
	Research and development			12,259			18,607			13,501			13,533
	General and administrative			6,256			6,211			6,143			6,704
	Loss from operations			(4,001	)		(8,335	)		(3,044	)		(2,963	)
	Interest, net			139			126			111			89
	Other			—			(18	)		(108	)		(28	)
	Net loss		$	(3,862	)	$	(8,227	)	$	(3,041	)	$	(2,902	)
	Basic and diluted net loss per share(1)		$	(0.11	)	$	(0.23	)	$	(0.08	)	$	(0.08	)
	Weighted average common shares			35,930,265			35,991,402			36,077,440			36,146,061
	outstanding – basic and diluted(2)
		-1	Per common share amounts for the quarters and full years have been calculated separately. Accordingly, the sum of quarterly amounts may not equal the annual amount because of differences in the weighted average common shares outstanding during each period, principally due to the effect of share issuances by the Company during the year.
		-2	Diluted weighted average common shares outstanding are identical to basic weighted average common shares outstanding and diluted net loss per share is identical to basic net loss per share for all quarters of 2013 because common share equivalents are excluded from the calculations of diluted weighted average common shares outstanding for those quarters, as their effect is anti-dilutive.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation
	The accompanying consolidated financial statements include the accounts of Endocyte, Inc. and its subsidiaries and all intercompany amounts have been eliminated. The consolidated financial statements are prepared in conformity with U.S. generally accepted accounting principles (“GAAP”). Subsequent events have been evaluated through the date of issuance, which is the same as the date this Form 10-K is filed with the Securities and Exchange Commission.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual amounts may differ from those estimates.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents
	The Company considers cash and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents consist primarily of money market instruments that are maintained by an investment manager.
Investment, Policy [Policy Text Block]	Investments
	Investments consist primarily of investments in U.S. Treasuries, U.S. Government agency obligations and corporate debt securities, which could also include commercial paper, that are maintained by an investment manager. U.S. government agency investments relate to investments in Fannie Mae, Freddie Mac and Federal Home Loan Bank. Management determines the appropriate classification of marketable securities at the time of purchase and reevaluates such classification as of each balance sheet date. Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in other comprehensive income. Realized gains and losses and declines in value judged to be other-than-temporary on available-for-sale securities are included in other income. The Company considers and accounts for other-than-temporary impairments according to the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 320, Investments — Debt and Equity Securities (“ASC 320”). The cost of securities sold is based on the specific-identification method. Discounts and premiums on debt securities are amortized to interest income and expense over the term of the security.
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment
	Property and equipment are stated at cost and are being depreciated using the straight-line method over estimated useful lives, which range from three to seven years.
Licenses And Patents [Policy Text Block]	Licenses and Patents
	Licenses and patent costs are expensed as incurred as the Company does not believe there is an alternate future use for the costs. Licenses are classified as research and development and patents are classified as general and administrative expenses in the consolidated statements of operations.
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Long-Lived Assets
	The Company reviews long-lived assets, including property and equipment, for impairment when events or changes in business conditions indicate that their full carrying value may not be fully recoverable.
Lease, Policy [Policy Text Block]	Leases
	The Company evaluates all leases to determine whether they should be accounted for as operating or capital leases.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition
	The Company recognizes revenues from license and collaboration agreements when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the fee is fixed or determinable, and there is reasonable assurance that the related amounts are collectible in accordance with ASC Topic 605, Revenue Recognition (“ASC 605”). The Company’s license and collaboration agreements may contain multiple elements, including grants of licenses to intellectual property rights, agreement to provide research and development services and other deliverables. The deliverables under such arrangements are evaluated under ASC Subtopic 605-25, Multiple-Element Arrangements (“ASC 605-25). Under ASC 605-25, each required deliverable is evaluated to determine whether it qualifies as a separate unit of accounting based on whether the deliverable has “stand-alone value” to the customer. The arrangement’s consideration that is fixed or determinable, excluding contingent milestone payments, is then allocated to each separate unit of accounting based on the relative selling price of each deliverable. In general, the consideration allocated to each unit of accounting is recognized as the related goods or services are delivered, limited to the consideration that is not contingent upon future deliverables.
	Upfront payments for licensing the Company's intellectual property are evaluated to determine if the licensee can obtain stand-alone value from the license separate from the value of the research and development services and other deliverables in the arrangement to be provided by the Company. If at the inception of an arrangement the Company determines that the license does not have stand-alone value separate from the research and development services or other deliverables, the license, services and other deliverables are combined as one unit of account and upfront payments are recorded as deferred revenue on the balance sheet and are recognized in a manner consistent with the final deliverable. Subsequent to the inception of an arrangement, the Company evaluates the remaining deliverables for separation as items in the arrangement are delivered. When stand-alone value is identified, the related consideration is recorded as revenue in the period in which the license or other intellectual property rights are delivered.
	In those circumstances where research and development services or other deliverables are combined with the license, and multiple services are being performed such that a common output measure to determine a pattern of performance cannot be discerned, the Company recognizes amounts received on a straight line basis over the performance period. Such amounts are recorded as collaboration revenue. Any subsequent reimbursement payments, which are contingent upon the Company’s future research and development expenditures, will be recorded as collaboration revenue and will be recognized on a straight-line basis over the performance period using the cumulative catch up method. The costs associated with these activities are reflected as a component of research and development expense in the statements of operations in the period incurred. In the event of an early termination of a collaboration agreement, any deferred revenue is recognized in the period in which all obligations of the Company under the agreement have been fulfilled.
	Milestone payments under collaborative arrangements are triggered either by the results of the Company’s research and development efforts, achievement of regulatory goals or by specified sales results by a third-party collaborator. Milestones related to the Company’s development-based activities may include initiation of various phases of clinical trials and applications and acceptance for product approvals by regulatory agencies. Due to the uncertainty involved in meeting these development-based milestones, the determination is made at the inception of the collaboration agreement whether the development-based milestones are considered to be substantive (i.e. not just achieved through passage of time). In addition, the amounts of the payments assigned thereto are considered to be commensurate with the enhancement of the value of the delivered intellectual property as a result of the Company’s performance. Because the Company’s involvement is necessary to the achievement of development-based milestones, the Company would account for development-based milestones as revenue upon achievement of the substantive milestone events. Milestones related to sales-based activities may be triggered upon events such as first commercial sale of a product or when sales first achieve a defined level. Since these sales-based milestones would be achieved after the completion of the Company’s development activities, the Company would account for the sales-based milestones in the same manner as royalties, with revenue recognized upon achievement of the milestone. Royalties based on reported sales of licensed products will be recognized based on contract terms when reported sales are reliably measurable and collectability is reasonably assured. To date, none of the Company's products have been approved and therefore the Company has not earned any royalty revenue from product sales. In territories where the Company and a collaborator may share profit, the revenue would be recorded in the period earned.
	The Company often is required to make estimates regarding drug development and commercialization timelines for compounds being developed pursuant to a collaboration agreement. Because the drug development process is lengthy and the Company’s collaboration agreements typically cover activities over several years, this approach often results in the deferral of significant amounts of revenue into future periods. In addition, because of the many risks and uncertainties associated with the development of drug candidates, the Company’s estimates regarding the period of performance may change in the future. Any change in the Company’s estimates or a termination of the arrangement could result in substantial changes to the period over which the revenues are recognized.
Research and Development Expense, Policy [Policy Text Block]	Research and Development Expenses
	Research and development expenses represent costs associated with the ongoing development of SMDCs and companion imaging agents and include salaries, supplies, and expenses for clinical trials. The Company records accruals for clinical trial expenses based on the estimated amount of work completed. The Company monitors patient enrollment levels and related activities to the extent possible through internal reviews, correspondence, and discussions with research organizations. In the event that a clinical trial is terminated early, the Company records, in the period of termination, an accrual for the estimated remaining costs to complete the trial.
	Upfront payments made in connection with business collaborations and research and development arrangements are evaluated under ASC Subtopic 730-20, Research and Development Arrangements. Upfront payments made in connection with business development collaborations are expensed as research and development costs, as the assets acquired do not have alternative future use. Amounts related to future research and development are capitalized as prepaid research and development and are expensed over the service period based upon the level of services provided. As of December 31, 2014, the Company had approximately $0.3 million of capitalized research and development costs included in prepaid expenses.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Stock-Based Compensation
	The Company accounts for its stock options pursuant to ASC Topic 718, Compensation — Stock Compensation (“ASC 718”), which requires the recognition of the fair value, or calculated value for nonpublic entities, of stock-based compensation in net income. Stock-based compensation consists of stock options, which are granted at exercise prices at or above the fair market value of the Company’s common stock on the dates of grant, service-based restricted stock units (“RSUs”) and performance-based RSUs (“PRSUs”). For PRSUs issued by the Company, stock-based compensation expense will be recognized when the Company determines that it is probable that the performance conditions will be achieved. For RSUs issued by the Company, stock-based compensation expense is recognized ratably over the service period. The Company used the calculated value method to measure its stock-based compensation prior to its initial public offering on February 4, 2011. The Company recognizes compensation cost based on the grant-date fair value estimated in accordance with the provisions of ASC 718.
Earnings Per Share, Policy [Policy Text Block]	Net Income (Loss) Per Share
	The Company calculates basic net income (loss) per share based on the weighted-average number of outstanding common shares. The Company calculates diluted net income (loss) per share based on the weighted-average number of outstanding common shares plus the effect of dilutive securities.
Regulatory Income Taxes, Policy [Policy Text Block]	Income Taxes
	The Company accounts for income taxes under the liability method in accordance with the provision of ASC Topic 740, Income Taxes (“ASC 740”). ASC 740 requires recognition of deferred taxes to provide for temporary differences between financial reporting and tax basis of assets and liabilities. Deferred taxes are measured using enacted tax rates expected to be in effect in a year in which the basis difference is expected to reverse. The Company continues to record a valuation allowance for the full amount of deferred tax assets, which would otherwise be recorded for tax benefits relating to operating loss and tax credit carryforwards, as realization of such deferred tax assets cannot be determined to be more likely than not.
	The Company accounts for uncertain income tax positions recognized in the financial statements in accordance with Accounting Standards Update (“ASU”) No. 2009-06. This guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return and provides guidance on derecognition of tax benefits, classification on the balance sheet, interest and penalties, accounting in interim periods, disclosure, and transition.
Segment Reporting, Policy [Policy Text Block]	Segment Information
	Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company performs clinical trials globally and has established a subsidiary in The Netherlands to assist in the administration of filing applications in Europe and a subsidiary in Switzerland for commercial pre-launch activities in Europe. The applications filed in Europe were withdrawn in May 2014 and the pre-launch activities in Europe ceased. The Company is in the process of dissolving Endocyte Europe GmbH, which should be completed in the first half of 2015. All long-lived assets are held in the U.S. The Company views its operations and manages its business in one operating segment.

Net_Income_Loss_Per_Share_Tabl

Net Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	As of December 31, 2012, 2013 and 2014 the following number of potential common stock equivalents were outstanding:
	Common stock equivalents
		Year Ended December 31,
		2012		2013		2014
	Outstanding common stock options		3,879,239		5,246,465		5,096,674
	Outstanding warrants		133,968		34,647		34,647
	Outstanding PRSUs		273,988		270,649		245,396
	Outstanding RSUs		—		—		161,439
	Shares to be purchased under the ESPP		—		—		2,894
	Total		4,287,195		5,551,761		5,541,050
Schedule of Weighted Average Number of Shares [Table Text Block]	The following weighted-average outstanding common stock options, warrants, RSUs and shares to be purchased under the ESPP were added to basic weighted-average common shares outstanding for the year ended December 31, 2014 to calculate diluted weighted-average shares outstanding because of their dilutive effect:
		Year Ended
		December 31,
		2014
	Outstanding common stock options		1,494,796
	Outstanding warrants		5,433
	Outstanding RSUs		14,128
	Shares to be purchased under the ESPP		1,392
	Total		1,515,749

Other_Comprehensive_Income_Los1

Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2014
Other Comprehensive Income (Loss), Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The accumulated balances related to each component of other comprehensive income (loss) were as follows:
		Foreign			Unrealized Net			Accumulated
		Currency			Gains (Losses)			Other
		Translation			on Securities			Comprehensive
		Gains (Losses)						Gains (Losses)
	Balance at December 31, 2011	$	(5,718	)	$	(546	)	$	(6,264	)
	Unrealized gain (loss)		707			78,204			78,911
	Net amount reclassified to net loss		—			102			102
	Other comprehensive income (loss)		707			78,306			79,013
	Balance at December 31, 2012		(5,011	)		77,760			72,749
	Unrealized gain (loss)		(6,805	)		(4,203	)		(11,008	)
	Net amount reclassified to net loss		—			(5,050	)		(5,050	)
	Other comprehensive income (loss)		(6,805	)		(9,253	)		(16,058	)
	Balance at December 31, 2013		(11,816	)		68,507			56,691
	Unrealized gain (loss)		(38,776	)		(165,285	)		(204,061	)
	Net amount reclassified to net income		—			3,442			3,442
	Other comprehensive income (loss)		(38,776	)		(161,843	)		(200,619	)
	Balance at December 31, 2014	$	(50,592	)	$	(93,336	)	$	(143,928	)
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
		Amount Reclassified from Accumulated									Affected Line Item in the
		Other Comprehensive Income (Loss)									Condensed Consolidated
											Statements of Operations and
	Details about Accumulated Other	Year Ended			Year Ended			Year Ended			Comprehensive Income (Loss)
	Comprehensive Income (Loss) Components	December 31,			December 31,			December 31,
		2012			2013			2014
	Unrealized Net Gains (Losses) on Securities	$	102		$	(5,050	)	$	3,442			Other income (expense)
	Total Reclassifications for the Period	$	102		$	(5,050	)	$	3,442

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Schedule of Cash, Cash Equivalents and Short-term Investments [Table Text Block]	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2013:
	Description	Cost		Level 1		Level 2		Fair Value
								(Carrying Value)
	Cash
	Cash	$	7,887,502	$	7,887,502	$	—	$	7,887,502
	Cash equivalents
	Money market funds		44,959,438		44,959,438		—		44,959,438
	Cash and cash equivalents	$	52,846,940	$	52,846,940	$	—	$	52,846,940
	Short-term investments (due within 1 year)
	U.S. government treasury obligations	$	5,009,194	$	5,013,850	$	—	$	5,013,850
	U.S. government agency obligations		33,598,370		33,609,886		—		33,609,886
	Corporate obligations		31,789,117		—		31,810,412		31,810,412
	Total short-term investments	$	70,396,681	$	38,623,736	$	31,810,412	$	70,434,148
	Long-term investments (due after 1 year through 2 years)
	U.S. government agency obligations	$	14,807,642	$	14,821,065	$	—	$	14,821,065
	Corporate obligations		10,743,707		—		10,750,594		10,750,594
	Total long-term investments	$	25,551,349	$	14,821,065	$	10,750,594	$	25,571,659
	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2014:
	Description	Cost		Level 1		Level 2		Fair Value
								(Carrying Value)
	Cash
	Cash	$	6,068,579	$	6,068,579	$	—	$	6,068,579
	Cash equivalents
	Money market funds		39,464,864		39,464,864		—		39,464,864
	Cash and cash equivalents	$	45,533,443	$	45,533,443	$	—	$	45,533,443
	Short-term investments (due within 1 year)
	U.S. government agency obligations	$	38,934,684	$	38,928,806	$	—	$	38,928,806
	Corporate obligations		40,659,036		—		40,607,405		40,607,405
	Total short-term investments	$	79,593,720	$	38,928,806	$	40,607,405	$	79,536,211
	Long-term investments (due after 1 year through 2 years)
	U.S. government treasury obligations	$	38,626,279	$	38,623,495	$	—	$	38,623,495
	U.S. government agency obligations		35,223,450		35,203,355		—		35,203,355
	Corporate obligations		7,947,275		—		7,934,327		7,934,327
	Total long-term investments	$	81,797,004	$	73,826,850	$	7,934,327	$	81,761,177

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Table Text Block]	Property and equipment consisted of the following:
		Estimated		December 31,
		Useful Lives		2013			2014
	Laboratory equipment		7	$	4,796,393		$	5,828,045
	Office equipment and software		3 – 7		972,789			1,225,298
	Leasehold improvements		7		348,901			400,018
	Assets not in service				503,208			23,836
					6,621,291			7,477,197
	Less accumulated depreciation				(2,781,865	)		(3,506,532	)
				$	3,839,426		$	3,970,665

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future minimum lease payments for noncancellable operating leases as of December 31, 2014, are as follows:
	2015	$	731,555
	2016		154,663
	2017		158,474
	2018		26,677
	2019		—
	Thereafter		—
	Total minimum lease payments	$	1,071,369

Stockholders_Equity_Deficit_Ta

Stockholders' Equity (Deficit) (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The weighted-average value of the individual options granted during 2012, 2013 and 2014 were determined using the following assumptions:
		Year Ended December 31,
		2012			2013			2014
	Weighted-average volatility		89.13	%		101	%		102.86	%
	Risk-free interest rate		1.1	%		1.31	%		1.98	%
	Weighted-average expected life (in years)		6.2			6.6			6.6
	Dividend yield		0	%		0	%		0	%
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	The Company’s stock option activity and related information are summarized as follows:
		Options			Weighted-Average			Weighted-Average			Aggregate
					Exercise Price			Remaining			Intrinsic Value
								Contractual Term
								(In Years)
	Outstanding at January 1, 2012		2,592,009		$	5.12
	Granted during year		1,492,395			4.61
	Exercised during year		(134,534	)		2.91
	Expired during year		(13,502	)		9.86
	Forfeited during year		(57,129	)		6.68
	Outstanding at December 31, 2012		3,879,239		$	4.96			7.5		$	16,198,044
	Exercisable at December 31, 2012		1,676,016			3.83			5.72			8,882,339
	Outstanding at January 1, 2013		3,879,239			4.96
	Granted during year		1,566,062			10.79
	Exercised during year		(188,699	)		3.42
	Expired during year		—			—
	Forfeited during year		(10,137	)		6.04
	Outstanding at December 31, 2013		5,246,465		$	6.76			7.39		$	22,002,357
	Exercisable at December 31, 2013		2,269,438			4.59			5.73			13,968,005
	Outstanding at January 1, 2014		5,246,465			6.76
	Granted during year		1,065,386			10.54
	Exercised during year		(399,654	)		3.23
	Expired during year		(244,121	)		9.17
	Forfeited during year		(571,402	)		10.49
	Outstanding at December 31, 2014		5,096,674		$	7.29			6.87		$	6,329,518
	Exercisable at December 31, 2014		2,695,278			5.89			5.68			4,986,059
Schedule of Nonvested Share Activity [Table Text Block]	The following is a rollforward of the Company’s nonvested stock options from January 1, 2012 to December 31, 2014.
		Options			Weighted-Average
					Grant Date Value
	Nonvested stock options at January 1, 2012		1,252,668		$	5.34
	Granted during year		1,492,395			3.42
	Vested during year		(484,711	)		4.51
	Expired during year		—			—
	Forfeited during year		(57,129	)		4.61
	Nonvested at December 31, 2012		2,203,223		$	4.24
	Nonvested stock options at January 1, 2013		2,203,223		$	4.24
	Granted during year		1,566,062			8.76
	Vested during year		(782,121	)		4.22
	Expired during year		—			—
	Forfeited during year		(10,137	)		4.58
	Nonvested at December 31, 2013		2,977,027		$	6.62
	Nonvested stock options at January 1, 2014		2,977,027		$	6.62
	Granted during year		1,065,386			8.62
	Vested during year		(1,069,615	)		6.61
	Expired during year		—			—
	Forfeited during year		(571,402	)		8.36
	Nonvested at December 31, 2014		2,401,396		$	7.07

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	A reconciliation of the expected income tax benefit (expense) computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2012, 2013, and 2014:
		December 31,
		2012			2013			2014
	Income tax computed at federal statutory tax rate		34	%		34	%		34	%
	State taxes, net of federal benefit		3.9	%		4.2	%		6.3	%
	State taxes rate change, net of federal benefit		—			—			30.4	%
	International operations		(0.2	)%		(2.1	)%		6.6	%
	Research and development credits		2.4	%		13.8	%		(22.6	)%
	Orphan drug credits		—			6.6	%		(57.4	)%
	Equity compensation		(2.2	)%		(2.5	)%		16.6	%
	Other		(0.2	)%		(1.3	)%		(2.1	)%
	Change in valuation allowance		(37.7	)%		(52.7	)%		(11.8	)%
	Total		0	%		0	%		0	%
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Net deferred tax assets and liabilities are comprised of the following:
		December 31,
		2013			2014
	Deferred tax assets
	Net operating loss carryforwards	$	65,678,000		$	71,074,000
	Research and development credit carryforwards		9,592,000			10,836,000
	Orphan Drug Credit		1,495,000			6,286,000
	Stock options		2,377,000			4,103,000
	Other		120,000			202,000
	Deferred tax assets		79,262,000			92,501,000
	Deferred tax liabilities
	Deferred revenue		(2,594,000	)		(16,408,000	)
	Property and equipment		(241,000	)		(316,000	)
	Deferred tax liabilities	$	(2,835,000	)	$	(16,724,000	)
	Net deferred tax asset before valuation allowance	$	76,427,000		$	75,777,000
	Less valuation allowance		(76,427,000	)		(75,777,000	)
	Net deferred tax assets	$	—		$	—

Restructuring_Costs_Tables

Restructuring Costs (Tables)	12 Months Ended
	Dec. 31, 2014
Restructuring Costs [Abstract]
Restructuring and Related Costs [Table Text Block]	The following table summarizes the restructuring accruals for the year ended December 31, 2014:
		Employee and			PROCEED			Total
		Contract			Trial
		Termination			Termination
		Accrual			Accrual
	Balance, January 1, 2014	$	—		$	—		$	—
	Charges for the year ended December 31, 2014		1,300,000			4,100,000			5,400,000
	Amounts paid in the year ended December 31, 2014		(1,300,000	)		(2,800,000	)		(4,100,000	)
	Balance, December 31, 2014	$	—		$	1,300,000		$	1,300,000

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Condensed Income Statement [Table Text Block]	The following table summarizes the unaudited statements of operations for each quarter of 2014 and 2013 (in thousands except share and per share amounts):
			Quarters Ended
			31-Mar			30-Jun			30-Sep			31-Dec
	2014
	Revenue		$	17,269		$	49,168		$	3,904		$	12
	Operating Expenses:
	Research and development			12,987			18,990			5,675			3,998
	General and administrative			7,501			7,968			4,007			4,201
	Income (loss) from operations			(3,219	)		22,210			(5,778	)		(8,187	)
	Interest, net			85			168			161			164
	Other			(7	)		(22	)		(58	)		(58	)
	Net income (loss)		$	(3,141	)	$	22,356		$	(5,675	)	$	(8,081	)
	Basic net income (loss) per share(1)		$	(0.09	)	$	0.54		$	(0.14	)	$	(0.19	)
	Diluted net income (loss) per share(1)		$	(0.09	)	$	0.52		$	(0.14	)	$	(0.19	)
	Weighted average common shares outstanding – basic			36,193,942			41,398,251			41,564,840			41,736,930
	Weighted average common shares outstanding – diluted			36,193,942			43,196,754			41,564,840			41,736,930
	Quarters Ended
			31-Mar			30-Jun			30-Sep			31-Dec
	2013
	Revenue		$	14,514		$	16,483		$	16,600		$	17,274
	Operating Expenses:
	Research and development			12,259			18,607			13,501			13,533
	General and administrative			6,256			6,211			6,143			6,704
	Loss from operations			(4,001	)		(8,335	)		(3,044	)		(2,963	)
	Interest, net			139			126			111			89
	Other			—			(18	)		(108	)		(28	)
	Net loss		$	(3,862	)	$	(8,227	)	$	(3,041	)	$	(2,902	)
	Basic and diluted net loss per share(1)		$	(0.11	)	$	(0.23	)	$	(0.08	)	$	(0.08	)
	Weighted average common shares			35,930,265			35,991,402			36,077,440			36,146,061
	outstanding – basic and diluted(2)
		-1	Per common share amounts for the quarters and full years have been calculated separately. Accordingly, the sum of quarterly amounts may not equal the annual amount because of differences in the weighted average common shares outstanding during each period, principally due to the effect of share issuances by the Company during the year.
		-2	Diluted weighted average common shares outstanding are identical to basic weighted average common shares outstanding and diluted net loss per share is identical to basic net loss per share for all quarters of 2013 because common share equivalents are excluded from the calculations of diluted weighted average common shares outstanding for those quarters, as their effect is anti-dilutive.

Nature_of_Business_and_Organiz1

Nature of Business and Organization (Details Textual) (USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Apr. 02, 2014
Nature Of Business And Organization [Line Items]
Stock Issued During Period, Shares, New Issues	5,175,000
Proceeds from Issuance of Common Stock	$101.90

Significant_Accounting_Policie2

Significant Accounting Policies (Details Textual) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Prepaid Expense, Current	$609,771	$3,200,924
Research and Development Arrangement [Member]
Significant Accounting Policies [Line Items]
Prepaid Expense, Current	$300,000

Net_Income_Loss_Per_Share_Deta

Net Income (Loss) Per Share (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential Common Stock Equivalents, Outstanding	5,541,050	5,551,761	4,287,195
Outstanding common stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential Common Stock Equivalents, Outstanding	5,096,674	5,246,465	3,879,239
Outstanding warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential Common Stock Equivalents, Outstanding	34,647	34,647	133,968
Outstanding PRSUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential Common Stock Equivalents, Outstanding	245,396	270,649	273,988
Outstanding RSUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential Common Stock Equivalents, Outstanding	161,439	0	0
Shares To be Purchased Under The ESPP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential Common Stock Equivalents, Outstanding	2,894	0	0

Net_Income_Loss_Per_Share_Deta1

Net Income (Loss) Per Share (Details 1)	12 Months Ended
	Dec. 31, 2014
Weighted Average Number Diluted Shares Outstanding Adjustment [Line Items]
Total Weighted Average Outstanding Common Stock equivalents	1,515,749
Outstanding common stock options [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment [Line Items]
Total Weighted Average Outstanding Common Stock equivalents	1,494,796
Outstanding warrants [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment [Line Items]
Total Weighted Average Outstanding Common Stock equivalents	5,433
Outstanding RSUs [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment [Line Items]
Total Weighted Average Outstanding Common Stock equivalents	14,128
Shares To be Purchased Under The ESPP [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment [Line Items]
Total Weighted Average Outstanding Common Stock equivalents	1,392

Other_Comprehensive_Income_Los2

Other Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign Currency Translation Gains (Losses), Beginning balance	($11,816)	($5,011)	($5,718)
Foreign Currency Translation Gains (Losses), Unrealized gain (loss)	-38,776	-6,805	707
Foreign Currency Translation Gains (Losses), Net amount reclassified to net loss	0	0	0
Foreign Currency Translation Gains (Losses), Other comprehensive income (loss)	-38,776	-6,805	707
Foreign Currency Translation Gains (Losses), Ending balance	-50,592	-11,816	-5,011
Unrealized Net Gains (Losses) on Securities, Beginning balance	68,507	77,760	-546
Unrealized Net Gains (Losses) on Securities,Unrealized gain (loss)	-165,285	-4,203	78,204
Unrealized Net Gains (Losses) on Securities, Net amount reclassified to net income (loss)	3,442	-5,050	102
Unrealized Net Gains (Losses) on Securities, Other comprehensive income (loss)	-161,843	-9,253	78,306
Unrealized Net Gains (Losses) on Securities, Ending balance	-93,336	68,507	77,760
Accumulated Other Comprehensive Gains (Losses), Beginning balance	56,691	72,749	-6,264
Accumulated Other Comprehensive Gains (Losses), Unrealized gain (loss)	-204,061	-11,008	78,911
Accumulated Other Comprehensive Gains (Losses), Net amount reclassified to net income (loss)	3,442	-5,050	102
Accumulated Other Comprehensive Gains (Losses), Other comprehensive income (loss)	-200,619	-16,058	79,013
Accumulated Other Comprehensive Gains (Losses), Ending balance	($143,928)	$56,691	$72,749

Other_Comprehensive_Income_Los3

Other Comprehensive Income (Loss) (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Comprehensive Income Loss [Line Items]
Amount Reclassified from Accumulated Other Comprehensive Loss, Unrealized Net Gains (Losses) on Securities	$3,442	($5,050)	$102
Other Income (Expense) [Member]
Other Comprehensive Income Loss [Line Items]
Amount Reclassified from Accumulated Other Comprehensive Loss, Unrealized Net Gains (Losses) on Securities	$3,442	($5,050)	$102

Investments_Details

Investments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash
Cash	$6,068,579	$7,887,502
Cash equivalents
Money market funds	39,464,864	44,959,438
Cash and cash equivalents	45,533,443	52,846,940	33,996,866	61,352,483
Short-term investments (due within 1 year)
Total short-term investments	79,536,211	70,434,148
Long-term investments (due after 1 year through 2 years)
Total long-term investments	81,761,177	25,571,659
US Treasury Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments		5,013,850
Long-term investments (due after 1 year through 2 years)
Total long-term investments	38,623,495
US Government Agencies Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	38,928,806	33,609,886
Long-term investments (due after 1 year through 2 years)
Total long-term investments	35,203,355	14,821,065
Corporate Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	40,607,405	31,810,412
Long-term investments (due after 1 year through 2 years)
Total long-term investments	7,934,327	10,750,594
Fair Value, Inputs, Level 1 [Member]
Cash
Cash	6,068,579	7,887,502
Cash equivalents
Money market funds	39,464,864	44,959,438
Cash and cash equivalents	45,533,443	52,846,940
Short-term investments (due within 1 year)
Total short-term investments	38,928,806	38,623,736
Long-term investments (due after 1 year through 2 years)
Total long-term investments	73,826,850	14,821,065
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments		5,013,850
Long-term investments (due after 1 year through 2 years)
Total long-term investments	38,623,495
Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	38,928,806	33,609,886
Long-term investments (due after 1 year through 2 years)
Total long-term investments	35,203,355	14,821,065
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	0	0
Long-term investments (due after 1 year through 2 years)
Total long-term investments	0	0
Fair Value, Inputs, Level 2 [Member]
Cash
Cash	0	0
Cash equivalents
Money market funds	0	0
Cash and cash equivalents	0	0
Short-term investments (due within 1 year)
Total short-term investments	40,607,405	31,810,412
Long-term investments (due after 1 year through 2 years)
Total long-term investments	7,934,327	10,750,594
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments		0
Long-term investments (due after 1 year through 2 years)
Total long-term investments	0
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	0	0
Long-term investments (due after 1 year through 2 years)
Total long-term investments	0	0
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	40,607,405	31,810,412
Long-term investments (due after 1 year through 2 years)
Total long-term investments	7,934,327	10,750,594
Cost [Member]
Cash
Cash	6,068,579	7,887,502
Cash equivalents
Money market funds	39,464,864	44,959,438
Cash and cash equivalents	45,533,443	52,846,940
Short-term investments (due within 1 year)
Total short-term investments	79,593,720	70,396,681
Long-term investments (due after 1 year through 2 years)
Total long-term investments	81,797,004	25,551,349
Cost [Member] | US Treasury Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments		5,009,194
Long-term investments (due after 1 year through 2 years)
Total long-term investments	38,626,279
Cost [Member] | US Government Agencies Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	38,934,684	33,598,370
Long-term investments (due after 1 year through 2 years)
Total long-term investments	35,223,450	14,807,642
Cost [Member] | Corporate Debt Securities [Member]
Short-term investments (due within 1 year)
Total short-term investments	40,659,036	31,789,117
Long-term investments (due after 1 year through 2 years)
Total long-term investments	$7,947,275	$10,743,707

Investments_Details_Textual

Investments (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]
Unrealized Gain on Securities	$18,858	$76,630
Unrealized Loss on Securities	112,194	8,122
Realized Gain on Securities	$1,429	$11,342

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$7,477,197	$6,621,291
Less accumulated depreciation	-3,506,532	-2,781,865
Property, Plant and Equipment, Net	3,970,665	3,839,426
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	5,828,045	4,796,393
Property, Plant and Equipment, Useful Life	7 years
Office equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,225,298	972,789
Office equipment and software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Office equipment and software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	400,018	348,901
Property, Plant and Equipment, Useful Life	7 years
Assets not in service [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$23,836	$503,208

Property_and_Equipment_Details1

Property and Equipment (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Depreciation, Total	$857,055	$674,725	$358,367

LongTerm_Debt_Details_Textual

Long-Term Debt (Details Textual) (USD $)	12 Months Ended			1 Months Ended		12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Aug. 31, 2010	Dec. 31, 2010
Debt Instrument [Line Items]
Gains (Losses) on Extinguishment of Debt	$0	$0	($992,281)
Interest Paid	0	0	655,834
Mid Cap Financial and Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					15,000,000
Proceeds from Bank Debt					10,000,000	5,000,000
Gains (Losses) on Extinguishment of Debt				992,000
Prepayment Penalty Rate				5.00%
Prepayment Penalty Amount				615,000
Debtor Reorganization Items, Write-off of Deferred Financing Costs and Debt Discounts				377,000
Warrants Issued to Acquire Number of Convertible Preferred Stock						64,674
Fair Value of Preferred Stock Warrants Issued						$219,322

Warrants_Details_Textual

Warrants (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2007
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$8.12
Warrants Maturity Date	2020
Common Stock [Member]
Class of Warrant or Right [Line Items]
Stock Issued During Period, Shares, Warants Exercised		47,791
GECC And Oxford [Member]
Class of Warrant or Right [Line Items]
Warrants Issued to Acquire Number of Convertible Preferred Stock			69,294
Warrants Maturity Date			2017

Leases_Details

Leases (Details) (USD $)	Dec. 31, 2014
Operating Leased Assets [Line Items]
2015	$731,555
2016	154,663
2017	158,474
2018	26,677
2019	0
Thereafter	0
Total minimum lease payments	$1,071,369

Leases_Details_Textual

Leases (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense, Net	$866,768	$784,531	$512,855

Stockholders_Equity_Deficit_De

Stockholders' Equity (Deficit) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Weighted-average volatility	102.86%	101.00%	89.13%
Risk-free interest rate	1.98%	1.31%	1.10%
Weighted-average expected life (in years)	6 years 7 months 6 days	6 years 7 months 6 days	6 years 2 months 12 days
Dividend yield	0.00%	0.00%	0.00%

Stockholders_Equity_Deficit_De1

Stockholders' Equity (Deficit) (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Outstanding, Beginning Balance	5,246,465	3,879,239	2,592,009
Options, Granted during year	1,065,386	1,566,062	1,492,395
Options, Exercised during year	-399,654	-188,699	-134,534
Options, Expired during year	-244,121	0	-13,502
Options, Forfeited during year	-571,402	-10,137	-57,129
Options, Outstanding, Ending Balance	5,096,674	5,246,465	3,879,239
Options, Exercisable	2,695,278	2,269,438	1,676,016
Weighted Average Exercise Price, Outstanding, Beginning Balance	$6.76	$4.96	$5.12
Weighted Average Exercise Price, Granted during year	$10.54	$10.79	$4.61
Weighted Average Exercise Price, Exercised during year	$3.23	$3.42	$2.91
Weighted average Exercise Price, Expired during year	$9.17	$0	$9.86
Weighted Average Exercise Price, Forfeited during year	$10.49	$6.04	$6.68
Weighted Average Exercise Price, Outstanding, Ending Balance	$7.29	$6.76	$4.96
Weighted Average Exercise Price, Exercisable	$5.89	$4.59	$3.83
Weighted Average Remaining Contractual Term, Outstanding, Ending Balance	6 years 10 months 13 days	7 years 4 months 20 days	7 years 6 months
Weighted Average Remaining Contractual Term, Exercisable	5 years 8 months 5 days	5 years 8 months 23 days	5 years 8 months 19 days
Aggregate Intrinsic Value, Outstanding, Ending Balance	$6,329,518	$22,002,357	$16,198,044
Aggregate Intrinsic Value, Exercisable	$4,986,059	$13,968,005	$8,882,339

Stockholders_Equity_Deficit_De2

Stockholders' Equity (Deficit) (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Options, Nonvested stock options, Beginning Balance	2,977,027	2,203,223	1,252,668
Options, Granted during year	1,065,386	1,566,062	1,492,395
Options, Vested during year	-1,069,615	-782,121	-484,711
Options, Expired during year	0	0	0
Options, Forfeited during year	-571,402	-10,137	-57,129
Options, Nonvested stock options, Ending Balance	2,401,396	2,977,027	2,203,223
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-Average Grant Date Value, Nonvested stock options, Beginning Balance	$6.62	$4.24	$5.34
Weighted-Average Grant Date Value, Granted during year	$8.62	$8.76	$3.42
Weighted-Average Grant Date Value, Vested during year	$6.61	$4.22	$4.51
Weighted-Average Grant Date Value, Expired during year	$0	$0	$0
Weighted-Average Grant Date Value, Forfeited during year	$8.36	$4.58	$4.61
Weighted-Average Grant Date Value, Nonvested stock options, Ending Balance	$7.07	$6.62	$4.24

Stockholders_Equity_Deficit_De3

Stockholders' Equity (Deficit) (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized	100,000,000	100,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$11,092,519	$13,900,183
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 7 months 6 days	1 year 9 months 18 days
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$7.29	$6.76	$4.96	$5.12
Stock Granted, Value, Share-based Compensation, Gross	9,188,595	13,725,956
Share-based Compensation, Total	8,025,261	6,059,005	3,022,693
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	7,072,923	3,303,701	2,216,038
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	2,934,244	1,884,651
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	5,096,674	5,246,465	3,879,239	2,592,009
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Vesting Term, Description	RSUs are service-based awards that will vest and be paid in four equal installments annually beginning in February 2015
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$11.11
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	1,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	161,439
Performance-based Restricted Stock Units (PRSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of Historical Forfeiture	6.49%
Share-based Compensation Arrangement by Share-based Payment Award, Vesting Term, Description	PRSUs will vest fifty percent based on the performance condition of commercial approval and fifty percent one year thereafter
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$2,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	245,396
Equity Incentive Plan 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized	8,071,563	6,625,563
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized	569,530	622,780
Stock Issued During Period, Shares, Employee Stock Purchase Plans	53,250
Share Price	$5.62

Income_Taxes_Details

Income Taxes (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Income tax computed at federal statutory tax rate	34.00%	34.00%	34.00%
State taxes, net of federal benefit	6.30%	4.20%	3.90%
State taxes rate change, net of federal benefit	30.40%	0.00%	0.00%
International operations	6.60%	-2.10%	-0.20%
Research and development credits	-22.60%	13.80%	2.40%
Orphan drug credits	-57.40%	6.60%	0.00%
Equity compensation	16.60%	-2.50%	-2.20%
Other	-2.10%	-1.30%	-0.20%
Change in valuation allowance	-11.80%	-52.70%	-37.70%
Total	0.00%	0.00%	0.00%

Income_Taxes_Details_1

Income Taxes (Details 1) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets
Net operating loss carryforwards	$71,074,000	$65,678,000
Research and development credit carryforwards	10,836,000	9,592,000
Orphan Drug Credit	6,286,000	1,495,000
Stock options	4,103,000	2,377,000
Other	202,000	120,000
Deferred tax assets	92,501,000	79,262,000
Deferred tax liabilities
Deferred revenue	-16,408,000	-2,594,000
Property and equipment	-316,000	-241,000
Deferred tax liabilities	-16,724,000	-2,835,000
Net deferred tax asset before valuation allowance	75,777,000	76,427,000
Less valuation allowance	-75,777,000	-76,427,000
Net deferred tax assets	$0	$0

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Operating Loss Carry Forward Expiration Period	2021
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	$179,478,000
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	235,422,000
For 2014 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	133,200,000
For 2015 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	39,000,000
For 2016 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	29,700,000
For 2017 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$16,800,000

Collaborations_Details_Textual

Collaborations (Details Textual) (USD $)	1 Months Ended			3 Months Ended								12 Months Ended			1 Months Ended
	Jul. 31, 2014	Apr. 30, 2012	Feb. 28, 2011	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 31, 2013	Dec. 31, 2009	Dec. 31, 1995
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable Upfront Payments Received		$120,000,000
Collaboration Revenue												70,353,483	64,870,919	34,682,111
Research and Development Expense	2,200,000		300,000	3,998	5,675	18,990	12,987	13,533	13,501	18,607	12,259	41,649,389	57,898,971	35,670,418
Deferred Revenue								59,700,000					59,700,000
Licenses Revenue												52,700,000	51,500,000
License and Services Revenue												17,600,000	13,400,000
Additional Contingent Payable Upon Satisfaction Of Certain Criteria				5,900,000								5,900,000
Minimum Annual Royalty Payments Payable Until First Commercial Sale																	12,500
Maintenance Costs			25,000
Payments to Acquire in Process Research and Development		120,000,000
Future Milestone Payments																500,000
Royalty Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Minimum Annual Royalty Payments Payable Until First Commercial Sale																15,000
Minimum Annual Royalty Milestone Payments																100,000
Proceed Trial Termination [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and Development Expense												1,100,000
NMP [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable Upfront Payments Received															1,000,000
Deferred Revenue				900,000								900,000
Potential Milestone Payments												4,500,000			4,500,000
Merck [Member] | Proceed Trial Termination [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and Development Expense												500,000
Good Laboratory Practice [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment for Milestone Achieved												50,000
PSMA tubulysin [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment for Milestone Achieved												100,000
Folate Tubulysin [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment for Milestone Achieved													100,000
Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable Upfront Payments Received		5,000,000
Non Substantive Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable Upfront Payments Received		$5,000,000

RelatedParty_Transactions_Deta

Related-Party Transactions (Details Textual) (USD $)	1 Months Ended		3 Months Ended								12 Months Ended
	Jul. 31, 2014	Feb. 28, 2011	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]
Research and Development Expense	$2,200,000	$300,000	$3,998	$5,675	$18,990	$12,987	$13,533	$13,501	$18,607	$12,259	$41,649,389	$57,898,971	$35,670,418
Proceeds from License Fees Received														191,000
License and Maintenance Revenue											20,000	20,000
Research and Development Expense [Member]
Related Party Transaction [Line Items]
Reimbursable Research And Development Expenses											50,614	27,394
Patents [Member]
Related Party Transaction [Line Items]
Reimbursement Revenue														50,000
Chief Science Officer [Member]
Related Party Transaction [Line Items]
Research and Development Expense											$1,000,000	$824,559	$788,737

Retirement_Plans_Details_Textu

Retirement Plans (Details Textual) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Defined Contribution Plan, Employer Discretionary Contribution Amount	$0.30

Restructuring_Costs_Details

Restructuring Costs (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Balance, January 1, 2014	$0
Charges for the year ended December 31, 2014	5,400,000
Amounts paid in the year ended December 31, 2014	-4,100,000
Balance, December 31, 2014	1,300,000
Employee And Contract Termination [Member]
Balance, January 1, 2014	0
Charges for the year ended December 31, 2014	1,300,000
Amounts paid in the year ended December 31, 2014	-1,300,000
Balance, December 31, 2014	0
Proceed Trial Termination [Member]
Balance, January 1, 2014	0
Charges for the year ended December 31, 2014	4,100,000
Amounts paid in the year ended December 31, 2014	-2,800,000
Balance, December 31, 2014	$1,300,000

Restructuring_Costs_Details_Te

Restructuring Costs (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$1,300,000	$0
Proceed Trial Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	4,100,000
Restructuring Reserve	1,300,000	0
Employee Severance and Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	$1,300,000

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data (unaudited) (Details) (USD $)	1 Months Ended		3 Months Ended																12 Months Ended
	Jul. 31, 2014	Feb. 28, 2011	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Data Unaudited [Line Items]
Revenue			$12		$3,904		$49,168		$17,269		$17,274		$16,600		$16,483		$14,514		$70,353,483	$64,870,919	$34,682,111
Operating Expenses:
Research and development	2,200,000	300,000	3,998		5,675		18,990		12,987		13,533		13,501		18,607		12,259		41,649,389	57,898,971	35,670,418
General and administrative			4,201		4,007		7,968		7,501		6,704		6,143		6,211		6,256		23,677,366	25,313,731	15,054,369
Income (loss) from operations			-8,187		-5,778		22,210		-3,219		-2,963		-3,044		-8,335		-4,001		5,026,728	-18,341,783	-16,042,676
Interest, net			164		161		168		85		89		111		126		139
Other			-58		-58		-22		-7		-28		-108		-18		0		-144,698	-153,702	-947,834
Net income (loss)			($8,081)		($5,675)		$22,356		($3,141)		($2,902)		($3,041)		($8,227)		($3,862)		$5,459,477	($18,032,438)	($17,291,758)
Basic net income (loss) per share (in dollars per share)			($0.19)	[1]	($0.14)	[1]	$0.54	[1]	($0.09)	[1]									$0.14	($0.50)	($0.48)
Diluted net income (loss) per share (in dollars per share)			($0.19)	[1]	($0.14)	[1]	$0.52	[1]	($0.09)	[1]									$0.13	($0.50)	($0.48)
Weighted average common shares outstanding - basic (in shares)			41,736,930		41,564,840		41,398,251		36,193,942										40,242,352	36,036,996	35,858,757
Weighted average common shares outstanding - diluted (in shares)			41,736,930		41,564,840		43,196,754		36,193,942										41,758,101	36,036,996	35,858,757
Basic and diluted net loss per share (in dollars per share)											($0.08)	[1]	($0.08)	[1]	($0.23)	[1]	($0.11)	[1]
Weighted average common shares outstanding - basic and diluted (in shares)											36,146,061	[2]	36,077,440	[2]	35,991,402	[2]	35,930,265	[2]
[1]	Per common share amounts for the quarters and full years have been calculated separately. Accordingly, the sum of quarterly amounts may not equal the annual amount because of differences in the weighted average common shares outstanding during each period, principally due to the effect of share issuances by the Company during the year.
[2]	Diluted weighted average common shares outstanding are identical to basic weighted average common shares outstanding and diluted net loss per share is identical to basic net loss per share for all quarters of 2013 because common share equivalents are excluded from the calculations of diluted weighted average common shares outstanding for those quarters, as their effect is anti-dilutive.