Stemline Therapeutics (STML) 10-Q 10 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Aug. 10, 2015
Document and Entity Information
Entity Registrant Name	STEMLINE THERAPEUTICS INC
Entity Central Index Key	1,264,587
Document Type	10-Q
Document Period End Date	Jun. 30, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		17,974,483
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2

Balance Sheets

Balance Sheets - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 13,933,233	$ 25,007,217
Short-term investments	39,937,245	28,976,147
Prepaid expenses and other current assets	2,224,697	1,636,808
Total current assets	56,095,175	55,620,172
Furniture and fixtures, net	153,333	230,000
Long-term investments	55,177,188	4,644,820
Total assets	111,425,696	60,494,992
Current liabilities:
Accounts payable and accrued expenses	5,844,926	4,473,842
Total current liabilities	5,844,926	4,473,842
Deferred grant revenue	793,712	607,999
Total liabilities	$ 6,638,638	$ 5,081,841
Stockholders' equity:
Preferred stock $0.0001 par value, 5,000,000 shares authorized, none issued and outstanding at June 30, 2015 and December 31, 2014
Common stock $0.0001 par value, 33,750,000 shares authorized at June 30, 2015 and December 31, 2014, 17,954,883 shares issued and outstanding at June 30, 2015 and 13,285,232 shares issued and outstanding at December 31, 2014	$ 1,796	$ 1,329
Additional paid-in capital	182,798,121	115,604,563
Accumulated other comprehensive income	14,061	3,000
Accumulated deficit	(78,026,920)	(60,195,741)
Total stockholders' equity	104,787,058	55,413,151
Total liabilities and stockholders' equity	$ 111,425,696	$ 60,494,992

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2015	Dec. 31, 2014
Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	33,750,000	33,750,000
Common stock, shares issued	17,954,883	13,285,232
Common stock, shares outstanding	17,954,883	13,285,232

Statement of Operations

Statement of Operations - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues:
Grant revenue	$ 121,429	$ 71,429	$ 242,858	$ 142,429
Operating expenses:
Research and development	8,199,397	4,090,590	14,234,884	11,207,446
General and administrative	2,152,638	2,038,011	3,962,703	4,034,294
Total operating expenses	10,352,035	6,128,601	18,197,587	15,241,740
Loss from operations	(10,230,606)	(6,057,172)	(17,954,729)	(15,099,311)
Other income	709	632	1,609	632
Interest income	76,181	43,842	121,941	86,054
Net loss	$ (10,153,716)	$ (6,012,698)	$ (17,831,179)	$ (15,012,625)
Net loss per common share:
Basic and Diluted (in dollars per share)	$ (0.58)	$ (0.47)	$ (1.05)	$ (1.16)
Weighted-average shares outstanding:
Basic and Diluted (in shares)	17,497,976	12,921,898	17,042,631	12,907,931

Statements of Comprehensive Los

Statements of Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statements of Comprehensive Loss
Net loss	$ (10,153,716)	$ (6,012,698)	$ (17,831,179)	$ (15,012,625)
Other comprehensive gain (loss):
Unrealized (loss) gain on investments	(21,236)	8,560	12,670	52,326
Reclassification adjustment for gain on investments included in net income	(709)	(632)	(1,609)	(632)
Other comprehensive gain (loss)	(21,945)	7,928	11,061	51,694
Comprehensive loss	$ (10,175,661)	$ (6,004,770)	$ (17,820,118)	$ (14,960,931)

Statement of Stockholders' Equi

Statement of Stockholders' Equity - 6 months ended Jun. 30, 2015 - USD ($)	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Total
Balance at Dec. 31, 2014	$ 1,329	$ 115,604,563	$ 3,000	$ (60,195,741)	$ 55,413,151
Balance (in shares) at Dec. 31, 2014	13,285,232
Increase (Decrease) in Stockholders' Equity
Restricted stock grants	$ 23	(23)
Restricted stock grants (in shares)	229,038
Issuance of common stock in connection with the secondary public offering	$ 435	64,105,937			64,106,372
Issuance of common stock in connection with the secondary public offerings (in shares)	4,353,877
Issuance of common stock in connection with the exercise of stock options	$ 9	354,742			354,751
Issuance of common stock in connection with the exercise of stock options (in shares)	86,736
Stock-based compensation expense		2,732,902			2,732,902
Net loss				(17,831,179)	(17,831,179)
Other comprehensive income			11,061		11,061
Balance at Jun. 30, 2015	$ 1,796	$ 182,798,121	$ 14,061	$ (78,026,920)	$ 104,787,058
Balance (in shares) at Jun. 30, 2015	17,954,883

Statements of Cash Flows

Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities
Net loss	$ (17,831,179)	$ (15,012,625)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	76,667	76,666
Stock-based compensation expense	2,732,902	2,022,098
Amortization of premium paid on marketable securities	89,388	137,672
Net gain on sale of marketable securities	(1,609)	(632)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(587,889)	(1,367,896)
Related party receivable		199,615
Accounts payable and accrued expenses	1,371,084	(780,736)
Deferred grant revenue	185,713	(142,143)
Net cash used in operating activities	(13,964,923)	(14,867,981)
Cash flows from investing activities
Purchase of marketable securities	(73,633,312)	(16,246,878)
Redemption of marketable securities	12,063,128	8,005,719
Net cash used in investing activities	(61,570,184)	(8,241,159)
Cash flows from financing activities
Proceeds from issuance of common stock, net	64,106,372
Proceeds from exercise of stock options	354,751	69,148
Net cash provided by financing activities	64,461,123	69,148
Net decrease in cash and cash equivalents	(11,073,984)	(23,039,992)
Cash and cash equivalents at beginning of period	25,007,217	44,200,420
Cash and cash equivalents at end of period	$ 13,933,233	$ 21,160,428

Organization and Basis of Prese

Organization and Basis of Presentation	6 Months Ended
	Jun. 30, 2015
Organization and Basis of Presentation
Organization and Basis of Presentation	1. Organization and Basis of Presentation Organization Stemline Therapeutics, Inc. (the “Company”) is a clinical stage biopharmaceutical company focused on discovering, acquiring, developing and commercializing proprietary oncology therapeutics that primarily target cancer stem cells (“CSCs”) and tumor bulk. The Company’s activities to date have primarily consisted of advancing its clinical stage drug candidates, SL-401 and SL-701, into and through clinical trials, formulating a clinical and regulatory development strategy, developing its preclinical pipeline including SL-801, optimizing its drug discovery platform, fortifying its intellectual property portfolio, identifying and acquiring additional product and technology rights, and raising capital. The Company was incorporated in Delaware on August 8, 2003 and has its principal office in New York, New York. Basis of Presentation The accompanying unaudited financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information and footnotes required by GAAP for complete financial statements. In the opinion of management, the accompanying financial statements include all adjustments (including normal recurring accruals) considered necessary for fair presentation of the Company’s financial position, results of operations and cash flows for the periods presented. Operating results for the current interim period are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2015 or any future periods . This Form 10-Q should be read in conjunction with the audited financial statements and accompanying notes in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 (“2014 Form 10-K”). The Company believes that its existing cash, cash equivalents, short-term investments and long-term investments will be sufficient to cover its cash flow requirements for at least the next two years. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to investments, property and equipment, accrued expenses, share-based compensation and income taxes. The estimates are based on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Results may differ from these estimates due to actual outcomes differing from those on which the Company bases its assumptions.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2015
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2 of the Notes to the Financial Statements included in the 2014 Form 10-K. There have been no changes to those policies. Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”), issued a comprehensive new revenue recognition Accounting Standards Update, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09). ASU 2014-09 provides guidance to clarify the principles for recognizing revenue. This guidance includes the required steps to achieve the core principle that 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. This guidance is effective for fiscal years and interim periods beginning after December 15, 2017. Early adoption is permitted for fiscal years and interim periods beginning after December 15, 2016. The Company expects to adopt this guidance when effective and is currently evaluating the effect that the updated standard will have on its financial statements and related disclosures. In August 2014, the FASB issued a new Accounting Standards Update ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014-15 provides guidance on management’s responsibility to evaluate whether there is substantial doubt about an organization’s ability to continue as a going concern and to provide related footnote disclosures. The guidance is effective for annual periods ending after December 15, 2016 and interim periods within annual periods beginning after December 15, 2016. Early adoption is permitted. The Company expects to adopt this guidance when effective and is currently evaluating the effect that the updated standard will have on its financial statements and related disclosures.

Liquidity and Capital Resources

Liquidity and Capital Resources	6 Months Ended
	Jun. 30, 2015
Liquidity and Capital Resources
Liquidity and Capital Resources	3. Liquidity and Capital Resources As of June 30 th , 2015, we have approximately $109 million in cash, cash equivalents, short and long-term investment securities. We primarily invest our cash, cash equivalents, short-term investments and long-term investments in U.S. Treasury and Agency securities and related money market funds and FDIC-insured bank certificates of deposit, with the balance in commercial bank operating accounts.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	6 Months Ended
	Jun. 30, 2015
Prepaid Expenses and Other Current Assets
Prepaid Expenses and Other Current Assets	4. Prepaid expenses and other current assets Prepaid expenses and other current assets consist of the following at June 30, 2015 and December 31, 2014 : June 30, December 31, 2015 2014 Grants Receivable — Prepaid insurance Prepaid third-party vendor costs Deposits Other Receivable Total $ $

Furniture and Fixtures

Furniture and Fixtures	6 Months Ended
	Jun. 30, 2015
Furniture and Fixtures
Furniture and Fixtures	5. Furniture and Fixtures Furniture and fixtures consist of the following at June 30, 2015 and December 31, 2014: June 30, December 31, 2015 2014 Office furniture and fixtures $ $ Less accumulated depreciation ) ) Furniture and fixtures, net $ $ Depreciation expense was $76,667 and $76,666 for the six-month periods ended June 30, 2015 and 2014, respectively. Depreciation expense was $38,333 for the three-months period ended June 30, 2015 and 2014, respectively.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2015
Fair Value Measurements
Fair Value Measurements	6. Fair Value Measurements The Company categorizes its financial instruments into a three-level fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). If the inputs used to measure fair value fall within different levels of the hierarchy, the category level is based on the lowest priority level input that is significant to the fair value measurement of the instrument. Financial assets recorded at fair value on the Company’s balance sheets are categorized as follows: Level 1: Unadjusted quoted prices for identical assets in an active market. Level 2: Quoted prices in markets that are not active or inputs that are observable either directly or indirectly for substantially the full-term of the asset. Level 2 inputs include the following: · quoted prices for similar assets in active markets, · quoted prices for identical or similar assets in non-active markets, · inputs other than quoted market prices that are observable, and · inputs that are derived principally from or corroborated by observable market data through correlation or other means. Level 3: Prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. Level 3 inputs reflect management’s own assessment about the assumptions a market participant would use in pricing the asset. There were no transfers between levels in the fair value hierarchy during any period presented herein. The Company’s financial assets and liabilities measured at fair value on a recurring basis at June 30, 2015 and December 31, 2014 consist of the following: June 30, 2015 Quoted Prices in Active Significant Markets for Other Significant Balance Identical Observable Unobservable at Assets Inputs Inputs June 30, (Level 1) (Level 2) (Level 3) 2015 Assets: Cash and cash equivalents $ $ — $ — $ Short-term investments — Long-term investments — Total assets at fair value $ $ $ — $ December 31, 2014 Quoted Prices in Active Significant Markets for Other Significant Balance Identical Observable Unobservable at Assets Inputs Inputs December 31, (Level 1) (Level 2) (Level 3) 2014 Assets: Cash and cash equivalents $ $ — $ — $ Short-term investments — — Long-term investments — — Total assets at fair value $ $ — $ — $ The following is a summary of cash equivalents and available-for-sale investments held by the Company at June 30, 2015 and December 31, 2014: June 30, 2015 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash equivalents: Money market funds $ $ — $ — $ Short-term investments: Fixed-income treasury portfolio: Fannie Mae — Federal farm credit bank — Federal home loan bank ) Freddie Mac ) Certificate of Deposits ) Total Short-term investments ) Long-term investments: Fixed-income treasury portfolio: Fannie Mae — ) Federal farm credit bank — ) Federal home loan bank ) Freddie Mac ) Certificate of Deposits ) Total Long-term investments ) Total $ $ $ ) $ December 31, 2014 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash equivalents: Money market funds $ $ — $ — $ Short-term investments: Fixed-income treasury portfolio: Fannie Mae — Federal farm credit bank ) Federal home loan bank ) Freddie Mac ) Total Short-term investments ) Long-term investments: Fixed-income treasury portfolio: Federal farm credit bank — ) Federal home loan bank — ) Freddie Mac — ) Total Long-term investments — ) Total $ $ $ ) $ At June 30, 2015 and December 31, 2014, the remaining contractual maturities of available-for-sale investments classified as current on the balance sheet were less than 12 months, and the remaining contractual maturities of available-for-sale investments classified as long-term were less than two years. There were no available-for-sale securities in a continuous unrealized loss position for greater than twelve months at June 30, 2015 and December 31, 2014. Fair Value of Financial Instruments The Company’s financial instruments consist principally of cash and cash equivalents, investments, other current assets, accounts payable and accrued expenses. Cash and cash equivalents, short-term investments and long-term investments are carried at fair value (see above). Financial instruments including other current assets, accounts payable and accrued expenses are carried at cost, which approximate fair value given their short-term nature.

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	6 Months Ended
	Jun. 30, 2015
Accounts Payable and Accrued Expenses
Accounts Payable and Accrued Expenses	7. Accounts Payable and Accrued Expenses Accounts payable and accrued expenses consist of the following at June 30, 2015 and December 31, 2014 : June 30, December 31, 2015 2014 Accrued research and development costs $ $ Accrued compensation Accrued professional fees Short-term portion of deferred revenue Other accrued liabilities Total $ $

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2015
Common Stock.
Common Stock	8. Common Stock In the first quarter of 2015, the Company completed an underwritten follow-on public offering, selling 3,800,000 shares at an offering price of $15.75 per share and the underwriters exercised in full their over-allotment option to purchase an additional 553,877 shares at an offering price of $15.75 per share (the “Secondary Offering”). Aggregate gross proceeds from the Secondary Offering were $68.6 million, and net proceeds received after underwriting fees and offering expenses were approximately $64.1 million. As of June 30, 2015 and December 31, 2014, the Company was authorized to issue 33,750,000 shares of common stock. Dividends on common stock will be paid when, and if, declared by the board of directors. Each holder of common stock is entitled to vote on all matters and is entitled to one vote for each share held. The Company will, at all times, reserve and keep available, out of its authorized but unissued shares of common stock, sufficient shares to effect the conversion of the shares of the stock options. In January 2013, the Company issued warrants to purchase up to 99,529 shares of the Company’s common stock. The warrants are exercisable for cash or on a cashless basis at a price per share equal to $15.00. The term of the warrants is four years and they expire on January 28, 2018.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Gain (Loss)	6 Months Ended
	Jun. 30, 2015
Accumulated Other Comprehensive Gain (Loss).
Accumulated Other Comprehensive Gain (Loss)	9. Accumulated Other Comprehensive Gain (Loss) The changes in accumulated balances for each component of other comprehensive gain (loss) are as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Balance at beginning of period $ $ ) $ $ ) Other comprehensive income (loss) before reclassification ) Amounts reclassified from accumulated other comprehensive income (loss)* ) ) ) ) Total other comprehensive income ) Balance at end of period $ $ $ $ *Amounts reclassified affect other income in the statements of operations.

Net (Loss) Income Per Common Sh

Net (Loss) Income Per Common Share	6 Months Ended
	Jun. 30, 2015
Net (Loss) Income Per Common Share
Net (Loss) Income Per Common Share	10. Net (Loss) Income Per Common Share The Company accounts for and discloses net income (loss) per share using the treasury stock method. Net income (loss) per common share, or basic income (loss) per share, is computed by dividing net income (loss) by the weighted-average number of common shares outstanding. Net income (loss) per common share assuming dilutions, or diluted income (loss) per share, is computed by reflecting the potential dilution from the exercise of in-the-money stock options, non-vested restricted stock and non-vested restricted stock units. The following table sets forth the computation of basic and diluted net loss per share for the periods indicated: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Basic and diluted net loss per common share calculation: Net loss $ ) $ ) $ ) $ ) Basic and diluted weighted-average common shares Basic and diluted net loss per share $ ) $ ) $ ) $ ) The difference between basic and diluted weighted-average common shares generally results from the assumption that dilutive stock options outstanding were exercised, dilutive restricted stock has vested, outstanding warrants are issued and the conversion of convertible notes. For the six -month periods ended June 30, 2015 and 2014, the Company reported a loss from operations and therefore, all potentially dilutive stock options, restricted stock, outstanding warrants and convertible notes as of such date were excluded from the computation of diluted net loss per share as their effect would have been anti-dilutive. The total shares of stock options, restricted stock, outstanding warrants and convertible notes that could potentially dilute earnings per share in the future, but which were not included in the calculation of diluted net loss per share because their affect would have been anti-dilutive were as follows: Six Months Ended June 30 2015 2014 Restricted stock Options outstanding Warrants Total

Revenue

Revenue	6 Months Ended
	Jun. 30, 2015
Revenue
Revenue	11. Revenue In October 2013, the Company entered into a contract agreement with The Leukemia and Lymphoma Society (“LLS”) which, among other activities, sponsors research relating to leukemia, lymphoma, Hodgkin’s disease and myeloma. LLS has agreed to provide funding to the Company of up to $3.5 million. Through June 30, 2015, the Company has received $1.5 million from LLS for milestones achieved. During July 2015, the company received an additional $1.0 million for a milestone achieved. The Company could receive the remaining $1.0 million based on the completion of certain milestone events. The Company has recognized approximately $0.2 million of revenue related to this funding for the six-month period ended June 30, 2015, which reflects six months of revenue recognized on a straight line basis, based on the Company’s best estimates of work performed and qualifying costs incurred. This agreement terminates when there are no longer any payment obligations.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2015
Income Taxes
Income Taxes	12. Income Taxes The Company did not record an income tax provision or benefit for the six and three-month periods ended June 30, 2015 and 2014, respectively, due to the fact that the Company cannot benefit from its net operating losses or other deferred tax assets. The Company has never had the ability to carry back losses to previous years to recover taxes paid and future utilization of these losses is uncertain. The Company files income tax returns in the United States and in the State of New York. The Company is not currently being audited by the Internal Revenue Service or any state taxing jurisdiction. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and their basis for income tax purposes and the tax effects of net operating loss and tax credit carryforwards. Valuation allowances reduce deferred tax assets to the amounts that are more likely than not to be realized. As of June 30, 2015, the Company has recorded additional deferred tax assets which are fully offset by a valuation allowance. Realization of the deferred tax assets is dependent on generating sufficient taxable income in the future. At present, the likelihood of the Company being able to fully utilize its deferred income tax benefits against future income is uncertain.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2015
Stock-Based Compensation
Stock-Based Compensation	13. Stock-Based Compensation The Company’s 2012 Stock Equity Incentive Plan (the “2012 Plan”), which was adopted by the board of directors and approved by the stockholders in July 2012, became effective immediately prior to the closing of the Company’s initial public offering. In addition, the Company’s 2004 Stock Option and Grant Plan (the “2004 Plan”) was terminated effective immediately prior to the closing of the Company’s initial public offering. The 1,819,839 options to purchase common stock and 34,506 restricted stock awards executed prior to the effective date of such termination remain in full force and effect pursuant to their terms and the terms of the 2004 Plan. The 2012 Plan initially authorized the Company to grant up to 1,663,727 shares of common stock to eligible employees, directors, and non-employee consultants and advisors to the Company in the form of options to purchase common stock of the Company at a price not less than the estimated fair value at the date of grant. Under the provisions of the 2012 Plan, no option will have a term in excess of 10 years. As of June 30, 2015, there were 793,674 shares of common stock available for future grants under the 2012 Plan. Total compensation cost that has been charged against operations related to the above plans was approximately $2.7 million and $2.0 million for the six-month periods ended June 30, 2015 and 2014, respectively. The Company does not recognize a tax benefit with respect to an excess stock compensation deduction until the deduction actually reduces the Company’s income tax liability. No income tax benefit was recognized in the statements of operations for share-based compensation arrangements for the six-month periods ended June 30, 2015 and 2014. The following table summarizes stock-based compensation related to the above plans by expense category for the three-month and six-month periods ended June 30, 2015 and 2014, respectively: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Research and development $ $ $ $ General and administrative Total $ $ $ $ Stock Options The Company grants stock options to employees, Directors and non-employee consultants, with exercise prices equal to the closing price of the underlying shares of the Company’s common stock on the date that the options are granted. Options granted have a term of 10 years from the grant date. Options granted to employees generally vest over a four-year period and options granted to Directors vest in equal yearly installments over a three-year period from the date of grant. Options to Directors are granted on an annual basis and represent compensation for services performed by the board of directors. Compensation cost for stock options granted to employees and Directors is charged against operations using the straight-line attribution method between the grant date for the option and each vesting date. The Company estimates the fair value of stock options on the grant date by applying the Black-Scholes option pricing valuation model. The application of this valuation model involves assumptions that are highly subjective, judgmental and sensitive in the determination of compensation cost. The weighted-average key assumptions used in determining the fair value of options granted for the three-month and six-month periods ended June 30, 2015 and 2014, respectively are as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Weighted-average volatility % % % % Weighted-average risk-free interest rate % % % % Weighted-average expected term in years Dividend yield % % % % The Company’s computation of stock-price volatility is based on the volatility rates of comparable publicly held companies over a period equal to the estimated useful life of the options granted by the Company. The Company’s computation of expected life was determined using the “simplified” method which is the midpoint between the vesting date and the end of the contractual term. The Company believes that it does not have sufficient reliable exercise data in order to justify the use of a method other than the “simplified” method of estimating the expected exercise term of employee stock option grants. The Company has paid no dividends to stockholders. The risk-free interest rate is based on the zero-coupon U.S. Treasury yield at the date of grant for a term equivalent to the expected term of the option. For the six-month period ended June 30, 2015, the Company issued 86,736 shares of the Company’s common stock upon the exercise of outstanding stock options and received proceeds of $354,751. As of June 30, 2015, there was approximately $9.1 million of unrecognized compensation cost, adjusted for estimated forfeitures, related to unamortized stock option compensation which is expected to be recognized over a remaining weighted-average period of approximately 2.71 years. Total unrecognized compensation cost will be adjusted for future changes in estimated forfeitures. The following table summarizes the activity related to the Company’s stock options for the six months ended June 30, 2015: Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2014 $ Options granted Options exercised ) Options forfeited ) Outstanding at June 30, 2015 $ $ Options exercisable at June 30, 2015 $ $ The aggregate intrinsic value in the previous table reflects the total pretax intrinsic value (the difference between the Company’s closing stock price on the last trading day of the quarter ended June 30, 2015 and the exercise price of the options, multiplied by the number of in-the-money stock options) that would have been received by the option holders had all option holders exercised their options on June 30, 2015. The intrinsic value of the Company’s stock options changes based on the closing price of the Company’s common stock. The total intrinsic value of options exercised (the difference in the market price of the Company’s common stock on the exercise date and the price paid by the optionee to exercise the option) was approximately $1.1 million for the six-month period ended June 30, 2015. Restricted Stock The Company grants restricted stock to its employees, Directors, and non-employee consultants. Restricted stock is recorded as deferred compensation and charged against earnings on a straight-line basis over the vesting period, which ranges from one to four years in duration. Restricted stock may be granted to Directors and represents compensation for services performed on the Company’s board of directors. Restricted stock awards to Directors vest in equal installments over a three-year period from the grant date. Compensation cost for restricted stock is based on the award’s grant date fair value, which is the closing market price of the Company’s common stock on the grant date, multiplied by the number of shares awarded. The following table summarizes the activity related to the Company’s restricted stock for the three months ended June 30, 2015: Number of Shares Weighted- Average Grant Date Fair Value Per Share Outstanding at December 31, 2014 $ Shares granted Shares vested ) Shares forfeited — — Outstanding at June 30, 2015 $ For the six-month period ended June 30, 2015, the Company granted 229,038 shares of restricted stock, at a weighted-average grant date fair value of $14.86 per share amounting to approximately $3.4 million in total aggregate fair value. As of June 30, 2015, 441,274 shares remained unvested and there was approximately $5.3 million of unrecognized compensation cost related to restricted stock which is expected to be recognized over a remaining weighted-average period of approximately 3.0 years. The total fair value of restricted stock vested during the six-month period ended June 30, 2015 and June 30, 2014 was approximately $1.3 million and $0.6 million, respectively. Awards Granted to Non-Employee Consultants The Company periodically re-measures the fair value of stock-based awards issued to non-employees and records expense over the requisite service period. Total compensation cost charged against operations related to options granted to non-employees was approximately $0.1 million for the six-month periods ended June 30, 2015 and 2014, respectively.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2015
Commitments and Contingencies
Commitments and Contingencies	14. Commitments and Contingencies The Company has entered into research and development agreements with third-parties for the development of oncology products. These agreements require the Company to fund the development of such products and potentially make milestone payments and royalties on net sales in the future based on the Company’s successful development of the products. The timing and the amount of milestone payments in the future are not certain. Under the Company’s license agreements, upon achieving certain milestones largely consisting of late stage clinical trials and marketing approval, the Company could be required to pay up to a total of $110.8 million. From inception through June 30, 2015, the Company has paid or accrued $3.2 million in payments resulting from such agreements. Royalties, largely single digit, are payable on commercial sales. Scott and White Memorial Hospital In June 2006, the Company entered into a research and license agreement, as amended in December 2008, March 2010 and July 2011 (collectively the “S&W Agreement”), with Scott and White Memorial Hospital and Scott, Sherwood and Brindley Foundation, and its affiliate Scott and White Clinic (collectively “S&W”) for the rights to SL-401 and SL-501. SL-401 is a clinical stage targeted therapy directed to the interleukin-3 receptor, or IL-3R, and is being developed to treat patients with hematologic cancers. SL-501 is a next generation IL-3R-targeted therapy and is in preclinical development. The Company is required to pay single-digit royalties on sales of these products, if any, and a percentage of upfront payments the Company may receive from a sublicensee. The S&W Agreement will expire in its entirety upon the later of (i) the 10th anniversary of the first commercial sale of a product, or (ii) the expiration of the last issued patent claiming or covering a product. The Company may terminate the S&W Agreement at its sole discretion at any time after a specified number of days following written notice and either party may terminate for a material breach of the agreement that is not cured within a specified number of days. University of Pittsburgh In September 2009, the Company entered into an exclusive license agreement with the University of Pittsburgh (“UP”) that covers patent rights claiming composition of a shortened variant of the IL-13Rα2 peptide (the “UP Agreement”) utilized by Stemline in its SL-701 composition. The Company paid UP an upfront license fee that was expensed to research and development cost for the year ended December 31, 2009. In addition to the upfront payment, the Company is required to pay annual fees, milestones (which are contingent upon achievement of pre-defined clinical, regulatory and commercial events), and, upon regulatory approval, single-digit royalties on net sales, and a percentage of non-royalty revenue from sublicensees, which decreases if the applicable sublicense agreement is entered into after a certain clinical milestone has been met. The UP Agreement will expire in its entirety upon the expiration of the last issued patent claiming or covering the product. The Company may terminate the UP Agreement at its sole discretion at any time after a specified number of days following written notice and UP may terminate for a material breach of the agreement by the Company that is not cured within a specified number of days. In March 2012, the Company entered into a non-exclusive license agreement with UP that covers patent rights claiming use of a shortened peptide of EphA2, which the Company may use for the diagnosis, treatment or prevention of diseases and tumors of the brain and is utilizing in its SL-701 composition. The Company paid UP an initial license fee and is required to pay UP annual license maintenance fees until the first commercial sale of a licensed product, a single-digit royalty on sales, and a minimum annual royalty following the first commercial sale of a licensed product. The UP Agreement will expire in its entirety upon the expiration of the last issued patent claiming or covering the product. The Company may terminate the UP Agreement at its sole discretion at any time after a specified number of days following written notice and UP may terminate for a material breach of the agreement by the Company that is not cured within a specified number of days. In March 2012, the Company entered into a non-exclusive license agreement with UP for the right to use certain information and data contained in the applications for investigational new drugs, or INDs, relating to clinical trials with an earlier version of SL-701 that were conducted by UP. The Company may use the information and data for the development, manufacture, regulatory approval and commercialization of pharmaceutical products. The Company paid UP an initial license fee and will be required to make a payment following a specified regulatory milestone, and a percentage of non-royalty revenue it may receive from any sublicensees. The UP Agreement will expire in its entirety in March 2032 unless earlier terminated by a party. The Company may terminate the UP Agreement at its sole discretion at any time prior to incorporating or referencing the data or UP INDs, after a specified number of days following written notice, and UP may terminate for a material breach of the agreement by the Company that is not cured within a specified number of days or if the IL-13Rα2 license agreement is terminated. CanBas, Ltd. On December 26, 2014, the Company entered into a license agreement with CanBas, Ltd. (“CanBas”) for SL-801. SL-801 is a small molecule, reversible inhibitor of XPO1. Under the terms of the agreement, CanBas has granted us an exclusive, royalty-bearing, worldwide (excluding Japan, Korea, China and Taiwan) license, under certain patent rights, know-how and materials to research, develop, make, have made, formulate, use, sell, offer to sell and import SL-801, and any products containing or comprising such compound in finished dosage pharmaceutical form. The patent rights exclusively licensed to us under the agreement, which include issued patents in the U.S. and abroad, cover both composition of matter and use of SL-801. We have additional pending patent applications directed to SL-801 which would provide additional protection in certain non-U.S. territories. The Company is responsible to pay annual technical advisory fees over the next four years totaling 430 million Japanese Yen (JPY), if the clinical development continues over this time period. Additionally, the Company must pay CanBas tiered royalties based on aggregate net sales, by us or our sublicensees, of products containing the licensed compound until the latest date of a period of ten years following the first commercial sale of each product in each country; the date upon which there are no more valid claims or the expiration or termination of the last regulatory exclusivity period. The royalty rates start in the low single digits and are tiered up based on annual net sales. In the future, the Company may also be responsible, based on the achievement of specific clinical-development, regulatory and sales-based commercial milestones, for certain payments to CanBas of up to $86 million. The Company have sublicensing rights under the agreement, subject to our paying to CanBas a standard royalty percentage of the payments the Company receive from a sublicensee. The Company must exercise commercially reasonable efforts to develop and commercialize a licensed product and to achieve certain regulatory milestones within certain periods, subject to extensions based on unforeseen technical, scientific, intellectual property or regulatory issues. The agreement survives until the later of ten years following the first commercial sale of each product in each country; the date upon which there are no more valid claims; or the expiration or termination of the last regulatory exclusivity period, after which our license becomes fully paid, irrevocable, perpetual, non-exclusive and royalty-free. We may terminate the license for any or no reason upon 60 days advance written notice to CanBas. If either party breaches a material obligation under the agreement, and such obligation is not cured within a specified period of time following written notice from the other party, then the non-breaching party may terminate the agreement upon an additional written notice. Other Research and Development Agreements The Company has also licensed rights to additional technologies and other intellectual property relevant to its preclinical pipeline and drug discovery and development efforts. The Company is generally required to make upfront payments as well as other payments upon completion of certain preclinical, clinical, regulatory and/or sales milestones. In addition, these agreements generally require the Company to pay royalties on sales of the products arising from these agreements. These agreements generally permit the Company to terminate the agreement with no significant continuing obligation. As part of the agreements discussed above, the Company has committed to make potential future milestone payments to certain third-parties. These payments generally become due and payable only upon the achievement of certain developmental, regulatory and/or commercial milestones. Because the achievement of these milestones is neither probable nor reasonably estimable, the Company has not recorded a liability on its balance sheet for any such contingencies. Contractual Agreements In February 2013, the Company entered into a bioprocessing services agreement with a vendor for approximately $2.9 million if all services are performed under the contract. As of December 31, 2014, the contract services were performed on the initial work order and had been paid by the Company. During 2014 and 2015, the Company entered into new work order agreements with this vendor totaling approximately $4.1 million, with services to be rendered on these agreements through 2015. The Company has received and paid for services relating to these agreements in the amount of $3.1 million. The Company has agreements with contract research organizations, or CROs, in connection with our clinical programs. The Company’s total expenditures would be approximately $15.5 million assuming the successful advancement of its programs. Lease Agreement In July 2013, the Company entered into a leasing agreement with respect to its corporate offices at 750 Lexington Avenue, New York, New York, for a monthly rent of $50,625. The term of this lease agreement is 36 months. The Company’s future annual minimum lease payments for each of the following calendar years are as follows: Remainder of 2015 $ 2016 $ Rent expense charged to operations was $303,913 and $303,842 for the six-month periods ended June 30, 2015 and 2014, respectively. Rent expense is included in general and administrative expenses in the Company’s Statements of Operations.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2015
Summary of Significant Accounting Policies
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”), issued a comprehensive new revenue recognition Accounting Standards Update, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09). ASU 2014-09 provides guidance to clarify the principles for recognizing revenue. This guidance includes the required steps to achieve the core principle that 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. This guidance is effective for fiscal years and interim periods beginning after December 15, 2017. Early adoption is permitted for fiscal years and interim periods beginning after December 15, 2016. The Company expects to adopt this guidance when effective and is currently evaluating the effect that the updated standard will have on its financial statements and related disclosures. In August 2014, the FASB issued a new Accounting Standards Update ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014-15 provides guidance on management’s responsibility to evaluate whether there is substantial doubt about an organization’s ability to continue as a going concern and to provide related footnote disclosures. The guidance is effective for annual periods ending after December 15, 2016 and interim periods within annual periods beginning after December 15, 2016. Early adoption is permitted. The Company expects to adopt this guidance when effective and is currently evaluating the effect that the updated standard will have on its financial statements and related disclosures.

Prepaid Expenses and Other Cu23

Prepaid Expenses and Other Current Assets (Tables)	6 Months Ended
	Jun. 30, 2015
Prepaid Expenses and Other Current Assets
Schedule of prepaid expenses and other current assets	June 30, December 31, 2015 2014 Grants Receivable — Prepaid insurance Prepaid third-party vendor costs Deposits Other Receivable Total $ $

Furniture and Fixtures (Tables)

Furniture and Fixtures (Tables)	6 Months Ended
	Jun. 30, 2015
Furniture and Fixtures
Schedule of furniture and fixtures	June 30, December 31, 2015 2014 Office furniture and fixtures $ $ Less accumulated depreciation ) ) Furniture and fixtures, net $ $

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Measurements
Schedule of assets and liabilities measured at fair value on recurring basis	June 30, 2015 Quoted Prices in Active Significant Markets for Other Significant Balance Identical Observable Unobservable at Assets Inputs Inputs June 30, (Level 1) (Level 2) (Level 3) 2015 Assets: Cash and cash equivalents $ $ — $ — $ Short-term investments — Long-term investments — Total assets at fair value $ $ $ — $ December 31, 2014 Quoted Prices in Active Significant Markets for Other Significant Balance Identical Observable Unobservable at Assets Inputs Inputs December 31, (Level 1) (Level 2) (Level 3) 2014 Assets: Cash and cash equivalents $ $ — $ — $ Short-term investments — — Long-term investments — — Total assets at fair value $ $ — $ — $
Summary of available-for-sale investments held by the Company	June 30, 2015 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash equivalents: Money market funds $ $ — $ — $ Short-term investments: Fixed-income treasury portfolio: Fannie Mae — Federal farm credit bank — Federal home loan bank ) Freddie Mac ) Certificate of Deposits ) Total Short-term investments ) Long-term investments: Fixed-income treasury portfolio: Fannie Mae — ) Federal farm credit bank — ) Federal home loan bank ) Freddie Mac ) Certificate of Deposits ) Total Long-term investments ) Total $ $ $ ) $ December 31, 2014 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash equivalents: Money market funds $ $ — $ — $ Short-term investments: Fixed-income treasury portfolio: Fannie Mae — Federal farm credit bank ) Federal home loan bank ) Freddie Mac ) Total Short-term investments ) Long-term investments: Fixed-income treasury portfolio: Federal farm credit bank — ) Federal home loan bank — ) Freddie Mac — ) Total Long-term investments — ) Total $ $ $ ) $

Accounts Payable and Accrued 26

Accounts Payable and Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2015
Accounts Payable and Accrued Expenses
Schedule of components of accounts payable and accrued expenses	June 30, December 31, 2015 2014 Accrued research and development costs $ $ Accrued compensation Accrued professional fees Short-term portion of deferred revenue Other accrued liabilities Total $ $

Accumulated Other Comprehensi27

Accumulated Other Comprehensive Gain (Loss) (Tables)	6 Months Ended
	Jun. 30, 2015
Accumulated Other Comprehensive Gain (Loss).
Schedule of change in accumulated other comprehensive gain (loss)	Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Balance at beginning of period $ $ ) $ $ ) Other comprehensive income (loss) before reclassification ) Amounts reclassified from accumulated other comprehensive income (loss)* ) ) ) ) Total other comprehensive income ) Balance at end of period $ $ $ $ *Amounts reclassified affect other income in the statements of operations.

Net (Loss) Income Per Common 28

Net (Loss) Income Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2015
Net (Loss) Income Per Common Share
Schedule of computation of basic and diluted net loss per share	Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Basic and diluted net loss per common share calculation: Net loss $ ) $ ) $ ) $ ) Basic and diluted weighted-average common shares Basic and diluted net loss per share $ ) $ ) $ ) $ )
Schedule of total shares of stock options, restricted stock, outstanding warrants and convertible notes that could potentially dilute earnings per share in the future, but which were not included in the calculation of diluted net loss per share because their affect would have been anti-dilutive	Six Months Ended June 30 2015 2014 Restricted stock Options outstanding Warrants Total

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2015
Stock-Based Compensation
Schedule of stock-based compensation by expense category	Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Research and development $ $ $ $ General and administrative Total $ $ $ $
Schedule of weighted-average key assumptions used in determining the fair value of options	Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Weighted-average volatility % % % % Weighted-average risk-free interest rate % % % % Weighted-average expected term in years Dividend yield % % % %
Summary of stock option activity	Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2014 $ Options granted Options exercised ) Options forfeited ) Outstanding at June 30, 2015 $ $ Options exercisable at June 30, 2015 $ $
Summary of activity related to the Company's restricted stock	Number of Shares Weighted- Average Grant Date Fair Value Per Share Outstanding at December 31, 2014 $ Shares granted Shares vested ) Shares forfeited — — Outstanding at June 30, 2015 $

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2015
Commitments and Contingencies
Schedule of future minimum lease payments	Remainder of 2015 $ 2016 $

Organization and Basis of Pre31

Organization and Basis of Presentation (Details)	6 Months Ended
	Jun. 30, 2015
Organization and Basis of Presentation
Minimum term for which anticipated operating cash requirements are funded	2 years

Liquidity and Capital Resourc32

Liquidity and Capital Resources (Details) $ in Millions	Jun. 30, 2015USD ($)
Liquidity and Capital Resources
Cash, cash equivalents, short and long term investment balance	$ 109

Prepaid Epenses and Other Curre

Prepaid Epenses and Other Current Assets (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Prepaid Expenses and Other Current Assets
Grants Receivable	$ 1,000,000
Prepaid insurance	306,099	$ 46,748
Prepaid third-party vendor costs	185,436	654,643
Deposits	106,243	106,243
Other Receivable	626,919	829,174
Total	$ 2,224,697	$ 1,636,808

Furniture and Fixtures (Details

Furniture and Fixtures (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Furniture and fixtures
Less accumulated depreciation	$ (306,667)		$ (306,667)		$ (230,000)
Furniture and fixtures, net	153,333		153,333		230,000
Depreciation expense	38,333	$ 38,333	76,667	$ 76,666
Office furniture and fixtures
Furniture and fixtures
Office furniture and fixtures	$ 460,000		$ 460,000		$ 460,000

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Fair Value Measurements
Transfers of assets between Level 1 to Level 2	$ 0	$ 0
Transfers of assets between Level 2 to Level 1	0	0
Transfers of liabilities between Level 1 to Level 2	0	0
Transfers of liabilities between Level 2 to Level 1	0	0
Assets:
Short-term investments	39,937,245	28,976,147
Long-term investments	55,177,188	4,644,820
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	13,933,233	25,007,217
Short-term investments	33,263,530	28,976,147
Long-term investments	33,897,246	4,644,820
Total assets at fair value	81,094,009	58,628,184
Recurring basis | Significant Other Observable Inputs (Level 2)
Assets:
Short-term investments	6,673,715
Long-term investments	21,279,942
Total assets at fair value	27,953,657
Recurring basis | Estimated Fair Value
Assets:
Cash and cash equivalents	13,933,233	25,007,217
Short-term investments	39,937,245	28,976,147
Long-term investments	55,177,188	4,644,820
Total assets at fair value	$ 109,047,666	$ 58,628,184

Fair Value Measurements (Deta36

Fair Value Measurements (Details 2) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Available-for-sale investments
Total Gross Unrealized Gains	$ 27,846	$ 10,427
Total Gross Unrealized Losses	(13,785)	(7,426)
Short-term investments
Available-for-sale investments
Amortized Cost	39,930,712	28,966,410
Gross Unrealized Gains	9,726	10,427
Gross Unrealized Losses	(3,193)	(690)
Estimated Fair Value	$ 39,937,245	$ 28,976,147
Short-term investments | Maximum
Available-for-sale investments
Remaining contractual maturity	12 months	12 months
Short-term investments | Fannie Mae
Available-for-sale investments
Amortized Cost	$ 4,814,491	$ 4,863,371
Gross Unrealized Gains	1,919	2,338
Estimated Fair Value	4,816,410	4,865,709
Short-term investments | Federal farm credit bank
Available-for-sale investments
Amortized Cost	9,009,639	11,432,340
Gross Unrealized Gains	3,530	3,575
Gross Unrealized Losses		(73)
Estimated Fair Value	9,013,169	11,435,842
Short-term investments | Federal home loan bank
Available-for-sale investments
Amortized Cost	13,624,724	6,859,294
Gross Unrealized Gains	1,918	2,381
Gross Unrealized Losses	(1,878)	(567)
Estimated Fair Value	13,624,764	6,861,108
Short-term investments | Freddie Mac
Available-for-sale investments
Amortized Cost	5,808,196	5,811,405
Gross Unrealized Gains	1,733	2,133
Gross Unrealized Losses	(742)	(50)
Estimated Fair Value	5,809,187	5,813,488
Long-term investments
Available-for-sale investments
Amortized Cost	55,169,660	4,651,556
Gross Unrealized Gains	18,120
Gross Unrealized Losses	(10,592)	(6,736)
Estimated Fair Value	$ 55,177,188	$ 4,644,820
Long-term investments | Maximum
Available-for-sale investments
Remaining contractual maturity	2 years	2 years
Long-term investments | Fannie Mae
Available-for-sale investments
Amortized Cost	$ 3,011,695
Gross Unrealized Losses	(2,852)
Estimated Fair Value	3,008,843
Long-term investments | Federal farm credit bank
Available-for-sale investments
Amortized Cost	2,528,929	$ 1,000,455
Gross Unrealized Losses	(898)	(1,126)
Estimated Fair Value	2,528,031	999,329
Long-term investments | Federal home loan bank
Available-for-sale investments
Amortized Cost	14,265,483	2,250,965
Gross Unrealized Gains	11,914
Gross Unrealized Losses	(1,633)	(3,426)
Estimated Fair Value	14,275,764	2,247,539
Long-term investments | Freddie Mac
Available-for-sale investments
Amortized Cost	14,081,461	1,400,136
Gross Unrealized Gains	5,883
Gross Unrealized Losses	(2,736)	(2,184)
Estimated Fair Value	14,084,608	1,397,952
Estimated Fair Value
Available-for-sale investments
Total	106,936,103	56,633,107
Amortized Cost
Available-for-sale investments
Total	106,922,042	56,630,106
Money market funds | Amortized Cost.
Available-for-sale investments
Cash equivalents	11,821,670	23,012,140
Money market funds | Estimated Fair Value
Available-for-sale investments
Cash equivalents	11,821,670	$ 23,012,140
Certificates of Deposits | Short-term investments
Available-for-sale investments
Amortized Cost	6,673,662
Gross Unrealized Gains	626
Gross Unrealized Losses	(573)
Estimated Fair Value	6,673,715
Certificates of Deposits | Long-term investments
Available-for-sale investments
Amortized Cost	21,282,092
Gross Unrealized Gains	323
Gross Unrealized Losses	(2,473)
Estimated Fair Value	$ 21,279,942

Fair Value Measurements (Deta37

Fair Value Measurements (Details 3) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Fair Value Measurements
Available-for-sale securities in a continuous unrealized loss position for greater than twelve months	$ 0	$ 0

Accounts Payable and Accrued 38

Accounts Payable and Accrued Expenses (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Accounts payable and accrued expenses
Accrued research and development costs	$ 3,312,139	$ 1,762,997
Accrued compensation	873,639	1,696,728
Accrued professional fees	446,614	164,389
Short-term portion of deferred revenue	1,057,143	485,714
Other accrued liabilities	155,391	364,014
Total	$ 5,844,926	$ 4,473,842

Common Stock (Details)

Common Stock (Details)	Jan. 31, 2013$ / sharesshares	Jun. 30, 2015USD ($)item$ / sharesshares	Dec. 31, 2014shares
Common Stock.
Number of shares issued in initial public offering or in secondary public offering		3,800,000
Share price (in dollars per share) | $ / shares		$ 15.75
Number of shares issued pursuant to an option granted to the underwriters to cover over-allotments		553,877
Aggregate gross proceeds from secondary public offering | $		$ 68,600,000
Proceeds from secondary public offering net of underwriting fees and offering expenses | $		$ 64,106,372
Number of shares of common stock authorized to be issued		33,750,000	33,750,000
Number of votes to which holders of common shares are entitled for each share held | item		1
Number of shares of common stock that may be purchased by warrants	99,529
Exercisable price of warrants (in dollars per share) | $ / shares	$ 15
Term of warrants	4 years

Accumulated Other Comprehensi40

Accumulated Other Comprehensive Gain (Loss) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Gain (Loss).
Balance at the beginning of period	$ 36,006	$ (9)	$ 3,000	$ (43,775)
Other comprehensive income (loss) before reclassification	(21,236)	8,560	12,670	52,326
Amounts reclassified from accumulated other comprehensive income (loss)	(709)	(632)	(1,609)	(632)
Total other comprehensive income	(21,945)	7,928	11,061	51,694
Balance at the end of period	$ 14,061	$ 7,919	$ 14,061	$ 7,919

Net (Loss) Income Per Common 41

Net (Loss) Income Per Common Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic and diluted net loss per common share calculation:
Net loss attributable to common shareholders - basic and diluted	$ (10,153,716)	$ (6,012,698)	$ (17,831,179)	$ (15,012,625)
Basic and diluted weighted-average common shares	17,497,976	12,921,898	17,042,631	12,907,931
Basic and diluted net loss per share (in dollars per share)	$ (0.58)	$ (0.47)	$ (1.05)	$ (1.16)

Net (Loss) Income Per Common 42

Net (Loss) Income Per Common Share (Details 2) - shares	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Net Loss Per Common Share
Potentially dilutive securities excluded from the computation of earnings per share (in shares)	2,677,238	2,054,091
Restricted stock
Net Loss Per Common Share
Potentially dilutive securities excluded from the computation of earnings per share (in shares)	441,274	311,403
Options outstanding
Net Loss Per Common Share
Potentially dilutive securities excluded from the computation of earnings per share (in shares)	2,136,435	1,643,159
Warrants
Net Loss Per Common Share
Potentially dilutive securities excluded from the computation of earnings per share (in shares)	99,529	99,529

Revenue (Details)

Revenue (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended		21 Months Ended
	Jul. 31, 2015	Oct. 31, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015
Revenue
Maximum amount of grants to be received from the Leukemia and Lymphoma Society		$ 3,500,000
Grant proceeds received	$ 1,000,000						$ 1,500,000
Amount of grants to be received upon completion of certain milestone					$ 1,000,000
Grant revenue			$ 121,429	$ 71,429	$ 242,858	$ 142,429

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Jan. 31, 2013
Stock Option Plan
Tax benefits related to the stock-based compensation costs recognized	$ 0	$ 0
Options outstanding
Stock Option Plan
Number of options to purchase common stock outstanding (in shares)	2,136,435		1,643,532
Term of option	10 years
Restricted stock
Stock Option Plan
Number of restricted stock awards outstanding (in shares)	441,274		283,446
2004 Plan | Options outstanding
Stock Option Plan
Number of options to purchase common stock outstanding (in shares)				1,819,839
2004 Plan | Restricted stock
Stock Option Plan
Number of restricted stock awards outstanding (in shares)				34,506
2012 Plan
Stock Option Plan
Number of common stock shares initially authorized for grant	1,663,727
Term of option	10 years
Shares available for future grants	793,674

Stock-Based Compensation (Det45

Stock-Based Compensation (Details 2) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock-Based Compensation
Stock-based compensation expense	$ 1,491,058	$ 1,079,658	$ 2,732,902	$ 2,022,098
Research and development
Stock-Based Compensation
Stock-based compensation expense	905,805	713,179	1,669,796	1,354,896
General and administrative
Stock-Based Compensation
Stock-based compensation expense	$ 585,253	$ 366,479	$ 1,063,106	$ 667,202

Stock-Based Compensation (Det46

Stock-Based Compensation (Details 3) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Weighted average assumptions used to estimate the weighted average fair value of the options granted on the date of grant using the Black-Scholes option-pricing model
Proceeds from exercise of stock options			$ 354,751	$ 69,148
Options outstanding
Stock-Based Compensation
Term of option			10 years
Weighted average assumptions used to estimate the weighted average fair value of the options granted on the date of grant using the Black-Scholes option-pricing model
Weighted-average volatility (as a percent)	73.70%	87.19%	79.01%	88.90%
Weighted-average risk-free interest rate (as a percent)	1.92%	1.96%	1.86%	1.98%
Weighted-average expected term in year	6 years	6 years 18 days	6 years 2 months 9 days	6 years 2 months 12 days
Dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%
Dividends paid to stockholders			$ 0
Proceeds from exercise of stock options			354,751
Unrecognized compensation expense related to unvested stock options	$ 14,400,000		$ 14,400,000
Weighted average period over which unrecognized compensation expense is expected to be recognized			2 years 8 months 16 days
Options
Outstanding balance at the beginning of the period (in shares)			1,643,532
Options granted (in shares)			588,674
Options exercised (in shares)			(86,736)
Options forfeited (in shares)			(9,035)
Outstanding balance at the end of the period (in shares)	2,136,435		2,136,435
Options exercisable (in shares)	1,082,658		1,082,658
Weighted Average Exercise Price
Outstanding balance at the beginning of the period (in dollars per share)			$ 8.64
Options granted (in dollars per share)			14.94
Options exercised (in dollars per share)			4.09
Options forfeited (in dollars per share)			4.09
Outstanding balance at the end of the period (in dollars per share)	$ 10.58		10.58
Options exercisable (in dollars per share)	$ 5.95		$ 5.95
Weighted-Average Remaining Contractual Life
Outstanding balance			7 years 6 months 18 days
Options exercisable			6 years 1 month 24 days
Aggregate Intrinsic Value
Outstanding balance (in dollars)	$ 12,673,030		$ 12,673,030
Options exercisable (in dollars)	$ 10,958,776		10,958,776
Total intrinsic value of options exercised			$ 1,100,000
Options outstanding | Employees
Stock-Based Compensation
Vesting period			4 years
Options outstanding | Directors
Stock-Based Compensation
Vesting period			3 years

Stock-Based Compensation (Det47

Stock-Based Compensation (Details 4) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Performance Share Awards
Stock-based compensation expense	$ 1,491,058	$ 1,079,658	$ 2,732,902	$ 2,022,098
Non-employees
Performance Share Awards
Stock-based compensation expense			$ 100,000	100,000
Restricted stock
Number of Shares
Outstanding balance at the beginning of the period (in shares)			283,446
Shares granted			229,038
Shares vested			(71,210)
Outstanding balance at the end of the period (in shares)	441,274		441,274
Weighted Average Grant Date Fair Value Per Share
Outstanding balance at the beginning of the period (in dollars per share)			$ 19.36
Shares granted (in dollars per share)			14.86
Shares vested (in dollars per share)			17.95
Outstanding balance at the end of the period (in dollars per share)	$ 17.25		$ 17.25
Total aggregate fair value of stock granted			$ 3,400,000
Number of shares remained unvested	441,274		441,274
Unrecognized compensation expense related to unvested restricted stock	$ 5,300,000		$ 5,300,000
Remaining weighted-average period for recognizing unrecognized compensation cost			3 years
Total fair value of restricted stock vested			$ 1,300,000	$ 600,000
Restricted stock | Directors
Stock-Based Compensation
Vesting period			3 years
Restricted stock | Minimum
Stock-Based Compensation
Vesting period			1 year
Restricted stock | Maximum
Stock-Based Compensation
Vesting period			4 years

Commitments and Contingencies48

Commitments and Contingencies (Details) ¥ in Millions	Dec. 26, 2014JPY (¥)	Dec. 26, 2014USD ($)	Jul. 31, 2013USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2014USD ($)	Feb. 28, 2013USD ($)
Compensation Arrangements
Monthly lease rent			$ 50,625
Lease agreement term			36 months
Future minimum lease payments
Remainder of 2015				$ 303,750
2,016				303,750
Total				607,500
Rent expense				303,913	$ 303,842
Research and development agreements with third parties
License Agreements
Amount required to be paid upon achievement of certain milestones				110,800,000
Amount paid or accrued				3,200,000
Bioprocessing services agreement
Contractual Agreement
Contractual agreement value						$ 2,900,000
New Service Agreements
License Agreements
Amount paid				3,100,000
Contractual Agreement
Contractual agreement value				4,100,000
Contract research organizations agreement
Contractual Agreement
Contractual agreement value				$ 15,500,000
S&W Agreement
License Agreements
Expiry term				10 years
License Agreement Terms
License Agreements
Period over which the annual technical advisory fee is to be paid	4 years	4 years
Technical advisory fees | ¥	¥ 430
Expiry term	10 years	10 years
Amount required to be paid upon achievement of certain milestones		$ 86,000,000
Period of written notice for termination of agreement	60 days	60 days
Period following the first commercial sale until which additional payments are required to be made	10 years	10 years