Nephrogenex (NRXGQ) 10-K 29 Mar 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Mar. 28, 2016	Jun. 30, 2015
Document and Entity Information
Entity Registrant Name	NephroGenex, Inc.
Entity Central Index Key	1,338,095
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		12,947,518
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 30,175,671

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 18,830	$ 13,978
Restricted cash	25	0
Short-term investments	2,894	14,698
Prepaid expenses and other assets	965	309
Total current assets	22,714	28,985
Property and equipment, net	38	36
Other assets	294	210
Total assets	23,046	29,231
Current liabilities
Accounts payable	1,974	1,750
Accrued and other liabilities	3,403	1,405
Current portion of note payable	2,264	293
Total current liabilities	7,641	3,448
Note payable, less current portion	4,238	6,442
Other long-term liabilities	24	10
Total liabilities	11,903	9,900
Commitments and contingencies (notes 5 and 12)	0	0
Stockholders’ equity
Preferred stock	0	0
Common stock; $.001 par value; 100,000,000 shares authorized; 12,946,018 and 8,862,114 shares issued and outstanding at December 31, 2015 and 2014, respectively	13	9
Additional paid-in capital	91,816	77,149
Accumulated other comprehensive loss	(3)	(8)
Accumulated deficit	(80,683)	(57,819)
Total stockholders’ equity	11,143	19,331
Total liabilities and stockholders’ equity	$ 23,046	$ 29,231

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	12,946,018	8,862,114
Common stock, shares outstanding	12,946,018	8,862,114
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized	5,000,000
Preferred stock, shares issued	0
Preferred stock, shares outstanding	0

Statements of Comprehensive Los

Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Expenses:
Research and development	$ 15,306	$ 11,264
General and administrative	7,016	5,323
Total expenses	22,322	16,587
Loss from operations	(22,322)	(16,587)
Other income (expense):
Change in value of preferred stock warrants	0	(140)
Interest expense	(565)	(140)
Interest income	23	47
Net loss	$ (22,864)	$ (16,820)
Net loss per share - basic and diluted (in dollars per share)	$ (2.29)	$ (2.15)
Weighted average shares outstanding - basic and diluted (in shares)	10,005,451	7,827,519
Other comprehensive loss:
Unrealized income (loss) on short-term investments	$ 5	$ (8)
Comprehensive loss	$ (22,859)	$ (16,828)

Statement of Stockholders' Equi

Statement of Stockholders' Equity (Deficiency) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance (in shares) at Dec. 31, 2013		319,882
Balance at Dec. 31, 2013	$ (14,186)	$ 0	$ 26,789	$ 0	$ (40,999)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock at IPO, net of expenses of $3,767 (in shares)		3,100,000
Issuance of common stock at IPO, net of expenses of $3,767	33,433	$ 3	33,430
Issuance of common stock for preferred stock warrant (in shares)		593,589
Issuance of common stock for preferred stock warrant	7,124	$ 1	7,123
Issuance of common stock for convertible notes and accrued interest (in shares)		1,197,289
Issuance of common stock for convertible notes and accrued interest	8,645	$ 1	8,644
Issuance of common stock for preferred stock (in shares)		3,644,354
Issuance of common stock for preferred stock		$ 4	20
Issuance of common stock for restricted stock units (in shares)		7,000
Issuance of warrants with term loan	192		192
Stock based compensation	951		951
Other comprehensive loss	(8)			(8)
Net loss	(16,820)				(16,820)
Balance at Dec. 31, 2014	19,331	$ 9	77,149	(8)	(57,819)
Balance (in shares) at Dec. 31, 2014		8,862,114
Stock Issued During Period, Shares, Share-based Compensation, Gross		6,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock at IPO, net of expenses of $3,767 (in shares)		1,612,500
Issuance of common stock at IPO, net of expenses of $3,767	7,100	$ 2	7,098
Stock based compensation	1,475		1,475
Other comprehensive loss	5			5
Net loss	(22,864)				(22,864)
Issuance of common stock in at-the-market public offering, net of offering expenses of $98 (in shares)		308,541
Issuance of common stock in at-the-market public offering, net of offering expenses of $98	1,112		1,112
Issuance of common stock in PIPE offering, including warrants, net of offering expenses of $516 (in shares)		2,156,863
Issuance of common stock in PIPE offering, including warrants, net of offering expenses of $516	4,984	$ 2	4,982
Balance at Dec. 31, 2015	$ 11,143	$ 13	$ 91,816	$ (3)	$ (80,683)
Balance (in shares) at Dec. 31, 2015		12,946,018

Statement of Stockholders' Equ6

Statement of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Payment of initial public offering costs	$ 1,579	$ 3,737
Amended and Restated Certificate of Incorporation [Member]
Payment of initial public offering costs	964	$ 3,767
PIPE Offering [Member]
Payment of initial public offering costs	516
MLV & Co. LLC [Member]
Payment of initial public offering costs	$ 98

Statements of Cash Flows

Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net loss	$ (22,864,000)	$ (16,820,000)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities
Depreciation and amortization	11,000	4,000
Loss on disposal of fixed assets	3,000	0
Change in fair value of preferred stock warrants	0	140,000
Non-cash interest expense	176,000	95,000
Accretion of premium on investment activities	37,000	71,000
Accrued interest receivable	51,000	4,000
Stock based compensation expense	1,475,000	951,000
Changes in operating assets and liabilities
Prepaid expenses and other assets	(760,000)	(455,000)
Accounts payable, accrued and other liabilities	2,236,000	2,372,000
Net cash and cash equivalents used in operating activities	(19,635,000)	(13,638,000)
Investing activities
Change in restricted cash	(25,000)	0
Purchases of investments	(13,232,000)	(26,383,000)
Sales of investments	24,953,000	11,603,000
Property and equipment purchases	(16,000)	(29,000)
Net cash and cash equivalents provided by (used in) investing activities	11,680,000	(14,809,000)
Financing activities
Proceeds from issuance of note payable	0	6,880,000
Payments on term loan	(389,000)	0
Payment of debt issuance costs	0	(50,000)
Payment of offering costs	(1,579,000)	(3,737,000)
Proceeds from issuance of common stock and warrants	14,775,000	37,200,000
Net cash and cash equivalents provided by financing activities	12,807,000	40,293,000
Net increase in cash and cash equivalents	4,852,000	11,846,000
Cash and cash equivalents at beginning of year	13,978,000	2,132,000
Cash and cash equivalents at end of year	18,830,000	13,978,000
Supplemental disclosure of cash flow information
Cash paid for interest	390,000	12,000
Supplemental disclosure of non-cash financing activities
Unrealized gain (loss) on investments	5,000	(8,000)
Issuance of warrants	3,257	0
Conversion of convertible notes payable, accrued interest, preferred stock and warrants into common stock	$ 0	$ 15,793,000

Description of the Business and

Description of the Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business and Basis of Presentation	Description of Business and Basis of Presentation Description of Business NephroGenex, Inc. (the “Company”) was incorporated in Delaware on May 25, 2004. The Company is a drug development company focused on developing novel therapies for kidney disease. The Company acquired commercial rights to Pyridorin® and has initiated a Phase 3 clinical study in patients with diabetic nephropathy. The Company’s primary efforts to date have been devoted to raising capital, recruiting senior management and staff and conducting research and development activities. The Company has experienced net losses since its inception and, as of December 31, 2015, has an accumulated deficit of $ 80.7 million . The Company currently has no commercially approved products and has recognized no revenue since its inception in 2004. The Company does not expect to generate revenue from product sales unless and until it successfully completes development and obtains marketing approval for one or more of its product candidates, which it expect will take a number of years and is subject to significant uncertainty. Developing and commercializing a product requires significant time and capital and is subject to regulatory review and approval. There can be no assurance that the Company’s current products in development, if approved, will be successfully commercialized due to a variety of factors, including competition from other biotechnology and pharmaceutical companies. In September 2014, the Company registered to form NephroGenex International Limited, a wholly-owned subsidiary, in Dublin, Ireland. From inception to date, there have been no activities transacted in this wholly-owned subsidiary and thus has no results to be consolidated into the Company's financial statements. Recent Developments As further discussed in Note 13 - Subsequent Event , on February 24, 2016, the Company announced its plan to pause the clinical program of the Company's product candidate oral Pyridorin for the treatment of diabetic nephropathy, effect a restructuring of its operations and implement a strategic transaction. In addition, the Company announced that it has paid off its outstanding term loan as of February 23, 2016. The Company's evaluation of potential business alternatives entails numerous significant risks and uncertainties, including the risks and uncertainties set forth in Item 1A under the heading "Risk Factors" of this Annual Report on Form 10-K. There can be no assurance that the Company's evaluation of potential business alternatives will result in any transaction. Going Concern The Company's financial statements have been prepared on a basis which assumes that the Company will continue as a going concern and which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. The Company has incurred losses since its inception, expects to incur additional costs and requires additional capital to continue as a going concern. As a result, the Company will require additional funds and will continue to seek private or public equity to meet its capital requirements. Even if the Company does not have an immediate need for additional cash, it may seek access to the private or public equity markets if and when conditions are favorable. If such funds are not available, management may need to reassess its business plans. There is no assurance that such additional funds will be available for the Company to finance its operations on acceptable terms, if at all. As a result of the announcement in February 2016, the Company determined to suspend all development and clinical trials activities due to the lack of financial resources and to seek other potential business alternatives that may be available.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Presentation The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Reverse Stock Split On February 6, 2014, the Company effected a 1-for-6.5 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the conversion ratio for the Company’s outstanding Series A Preferred Stock. All share and per share amounts for the twelve month period ended December 31, 2014 presented in these financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect the reverse stock split and adjustment of the preferred share conversion ratios. Initial Public Offering On February 14, 2014, the Company completed its initial public offering of common stock (the “IPO”) pursuant to a registration statement that was declared effective on February 10, 2014. The Company sold 3,100,000 shares of its common stock, at a price of $ 12.00 . The Company received a total of $33.4 million in net proceeds after deducting underwriting discounts and commissions and offering expenses of approximately $ 3.8 million . Costs directly associated with the IPO were capitalized and recorded as deferred IPO costs prior to the closing of the IPO. These costs were recorded as a reduction of the proceeds received in arriving at the amount to be recorded as additional paid-in capital. Upon completion of the IPO, 3,644,354 shares of common stock were issued for the conversion of all outstanding shares of Series A Preferred stock, 1,197,289 shares of common stock were issued for the conversion of outstanding convertible notes and accrued interest and 593,589 aggregate shares of common stock were issued in connection with the settlement of the Company’s outstanding preferred stock warrant liability. Warrant Liability Certain warrants to purchase the Company’s capital stock had historically been classified as liabilities and were recorded at estimated fair value. At each reporting period, any change in fair value of the freestanding warrants was recorded as other (expense) income. The Company recorded $140,000 as other expense as as a result of the change in fair value of the preferred stock warrant liability for the years ended December 31, 2014. The preferred stock warrant liability was settled upon the closing of the IPO. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. Restricted Cash Restricted cash consists of deposits held by a financial institution as collateral for the Company's corporate credit card. Investments The Company invests in money market funds and certificates of deposits and considers all investments purchased with original maturity dates greater than three months and less than one year to be short-term investments. Those investments with original maturity dates greater than one year at each balance sheet date are considered to be long-term investments. As of December 31, 2015, all investments were classified as available-for-sale and had original maturity dates less than one year. These investments are carried at estimated fair value with unrealized gains and losses included in stockholders' equity. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income. Concentration of Credit Risk The Company invests its available cash balances in bank deposits, money market funds and certificates of deposit. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. Additionally, the Company has established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity. Property and Equipment Property and equipment consists of furniture, fixtures and computers. Property and equipment are carried at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the respective asset's estimated useful life. Maintenance and repairs that do not improve or extend the life of assets are expensed as incurred. When an asset is retired or disposed of, the cost and related accumulated depreciation are removed from the accounts and any resulting gains or losses are reflected within the statement of operations. Useful lives generally range from three to seven years. Fair Value of Financial Instruments As of December 31, 2015, financial instruments consist of cash and cash equivalents, short-term investments, a term loan, accounts receivable and accounts payable. The Company defines fair value (“FV”) as the price that would be received to sell an asset or paid to transfer a liability ("the exit price") in an orderly transaction between market participants at the measurement date. The FV hierarchy for inputs maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. The Company uses the following hierarchy of inputs to measure FV: • Level 1: Quoted prices in active markets for identical assets or liabilities; • Level 2: Inputs, other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities in active markets; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and • Level 3: Unobservable inputs that are supported by little or no market activity, which require the reporting entity to develop its own assumptions. The Company values investments using the most observable inputs available that are current as of the measurement date and classifies them according to the lowest level of inputs used. Observable inputs are inputs that market participants would use in pricing the asset or liability developed from market data obtained from independent sources. Unobservable inputs are those which reflect the Company’s judgment concerning the assumptions that market participants would use in pricing the asset or liability developed from the best information available under the circumstances. The Company targets investments principally in Level 1 and Level 2 cash equivalents and financial instruments and records them at FV. The Company did not rely on Level 3 inputs for the valuation of any investments at December 31, 2015 or December 31, 2014. The Company expects that the carrying values of cash equivalents will approximate FV because of their short maturities. The Company classifies as Level 2 investments in certificates of deposits and values them using the market approach based on significant other observable inputs including quoted prices in active markets for instruments that are similar or quoted prices in markets that are not traded on a daily basis for identical or similar instruments. The following table sets forth our financial instruments carried at FV within the ASC 820 hierarchy and using the lowest level of input as of December 31, 2015: Quoted Prices in Active Significant (in thousands) Markets Other Significant Balance For Identical Assets Observable Inputs Unobservable Inputs Assets: December 31, 2015 Level 1 Level 2 Level 3 Certificates of Deposit $ 7,142 $ — $ 7,142 $ — $ 7,142 $ — $ 7,142 $ — The following table sets forth our financial instruments carried at FV within the ASC 820 hierarchy and using the lowest level of input as of December 31, 2014: Quoted Prices in Active Significant (in thousands) Markets Other Significant Balance For Identical Assets Observable Inputs Unobservable Inputs Assets: December 31, 2014 Level 1 Level 2 Level 3 Certificates of Deposit $ 16,765 $ — $ 16,765 $ — Total Assets $ 16,765 $ — $ 16,765 $ — The Company recorded $140,000 as other expense as as a result of the change in fair value of the preferred stock warrant liability for the year ended December 31, 2014. Debt Issuance Costs Debt issuance costs represent legal and other direct costs related to the Company's outstanding loan. These costs are recorded as an asset on the accompanying balance sheets and are being amortized to interest expense utilizing the effective interest method through the earliest date at which the Company can be required to repay the notes. The balance of debt issuance costs was $27,000 and $48,000 for the years ended December 31, 2015 and 2014, respectively. Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses include personnel costs associated with research and development activities including non-cash share-based compensation, costs for third-party contractors to perform research, conduct clinical trials and manufacture drug supplies and materials. The Company accrues for costs incurred by external service providers, including contract research organizations and clinical investigators, based on its estimates of service performed and costs incurred. These estimates include the level of services performed by the third parties, patient enrollment in clinical trials, administrative costs incurred by the third parties, and other indicators of the services completed. Based on the timing of amounts invoiced by service providers, the Company may also record payments made to those providers as prepaid expenses that will be recognized as expense in future periods as the related services are rendered. Stock-Based Compensation The Company estimates the FV of stock options and stock purchase rights using a Black-Scholes option valuation model which requires the input of highly subjective assumptions, including the option’s expected life and the price volatility of the underlying stock. The Company uses the simplified method for estimating the expected term as provided by the Securities and Exchange Commission's Staff Accounting Bulletin No. 107. The simplified method calculates the expected term as the average time-to-vesting and the contractual life of the options. The expected stock price volatility assumption was determined by examining the historical volatilities of a group of industry peers. The FV of each option grant is estimated on the date of grant using the Black-Scholes option valuation model, and the resulting FV is expensed using the straight-line attribution method over the vesting period, which is the same as the requisite service period. Restricted stock units are measured at the FV of the Company's common stock on the date of grant and expensed over the period of vesting, which is the same as the requisite service period using the straight-line attribution method. The Company has also granted stock options to non-employees. Grants to non-employees are accounted for in accordance with Accounting Standards Codification ("ASC") 505-50 Equity – Based Payments to Non-Employees. The Company determines the fair value of share based awards granted to nonemployees similar to the way fair value of awards are determined for employees except that certain assumptions used in the Black-Scholes option-pricing model, such as expected life of the option, may be different and the fair value of each award is adjusted at the end of each period for any change in fair value from the previous valuation until the award vests. Recently Issued Accounting Pronouncements Occasionally, new accounting standards are issued or proposed by the Financial Accounting Standards Board (the “FASB”), or other standards-setting bodies that the Company adopts by the effective date specified within the standard. Unless otherwise discussed, standards that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption. I n August 2014, FASB issued Accounting Standards Update (“ASU”) No. 2014-15, “ Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” The amendments in this ASU are intended to define management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. Specifically, this ASU provides a definition of the term substantial doubt and requires an assessment for a period of one year after the date that the financial statements are issued (or available to be issued). It also requires certain disclosures when substantial doubt is alleviated as a result of consideration of management’s plans and requires an express statement and other disclosures when substantial doubt is not alleviated. The new standard will be effective for annual periods ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. We are currently evaluating the impact the adoption of this standard will have on the Company's financial statements and disclosures. In April 2015, the FASB issued ASU No. 2015-03, " Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs." The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this ASU. The new standard will be effective for reporting periods beginning after December 15, 2015, with early adoption permitted. The amendments should be applied on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new standard. We have not adopted this ASU as of December 31, 2015, but believe that the adoption of this ASU will not have a material impact on the Company's financial statements and related disclosures. In April 2015, the FASB issued ASU No. 2015-05, " Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement. " The amendments in this ASU provide guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The amendments do not change the accounting for a customer's accounting for service contracts. The new standard will be effective for annual periods ending after December 15, 2015, and interim periods thereafter, with early adoption permitted. We have not adopted this ASU as of December 31, 2015, but believe that the adoption of this ASU will not have a material impact on the Company's financial statements and related disclosures. In November 2015, the FASB issued ASU No. 2015-17, " Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes." This amendment requires deferred tax liabilities and assets to be classified as non-current in a classified statement of financial position, as opposed to separating the deferred tax liability and asset amounts into current and non-current amounts. The new standard will be effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods, with early adoption permitted. We are currently evaluating the impact the adoption of this standard will have on the Company's financial statements and disclosures.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of the Company’s common stock outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common share equivalents outstanding for the period determined using the treasury-stock method. Under the treasury-stock method earnings per share data is computed as if the common share equivalents were outstanding at the beginning of the period (or at the time of issuance, if later) and as if the funds obtained from exercise of the common stock equivalents were used to purchase common stock at the average market price during the period. If there is little or no market for the common stock, a reasonable estimate of FV shall be used. For purposes of this calculation, preferred stock, stock options, restricted stock units and warrants to purchase capital stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following table sets forth the computation of basic and diluted net loss per share in thousands, except share and per share data: Year Ended December 31, 2015 2014 Numerator: Net loss $ (22,864 ) $ (16,820 ) Denominator: Weighted average common shares outstanding 10,005,451 7,827,519 Net loss per share- basic and diluted $ (2.29 ) $ (2.15 ) Potentially dilutive securities not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows: 2015 2014 Common stock options 1,542,732 848,025 Restricted stock units 891,617 24,000 Common stock warrants 10,039,682 61,039

Balance Sheet Items

Balance Sheet Items	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Items	Balance Sheet Items Investments The following table summarizes the Company's available for sale investments as of December 31, 2015 (in thousands): Maturity Amortized Unrealized Unrealized Estimated Short-term Investments (in years) Cost Gains Loss Fair Value Certificates of Deposit 1 or less $ 2,897 $ — $ (3 ) $ 2,894 Total Investments $ 2,897 $ — $ (3 ) $ 2,894 The following table summarizes the Company's available for sale investments as of December 31, 2014 (in thousands): Maturity Amortized Unrealized Unrealized Estimated Short-term Investments (in years) Cost Gains Loss Fair Value Certificates of Deposit 1 or less $ 14,706 $ — $ (8 ) $ 14,698 Total Investments $ 14,706 $ — $ (8 ) $ 14,698 At each reporting date, the Company performs an evaluation of impairment to determine if the unrealized losses are other-than-temporary. For debt securities, management determines whether it intends to sell the impaired securities, and if there is no intent or expected requirement to sell, management considers whether it is likely that the amortized cost will be recovered. The Company does not consider unrealized losses on its debt investment securities to be credit-related. These unrealized losses relate to changes in interest rates and market spreads subsequent to purchase. The Company has not made a decision to sell securities with unrealized losses and believes it is more likely than not it would not be required to sell such securities before recovery of its amortized cost. There have been no other than temporary losses recognized in earnings. Property and Equipment As of December 31, 2015 and 2014 property and equipment were as follows (in thousands): Useful Life 2015 2014 Computer equipment 3-5 years $ 67 $ 54 Furniture and fixtures 7 years 66 66 Leasehold improvements 5.5 years 18 18 151 138 Less accumulated depreciation and amortization (113 ) (102 ) Property and equipment, net $ 38 $ 36 For the years ended December 31, 2015 and 2014, depreciation and amortization expense was approximately $11,000 and $4,000 , respectively. Accrued Liabilities As of December 31, 2015 and 2014 accrued liabilities were as follows (in thousands): 2015 2014 Accrued clinical trial expenses $ 2,432 $ 393 Accrued compensation 964 909 Other accruals 7 103 Total $ 3,403 $ 1,405

License Agreements

License Agreements	12 Months Ended
	Dec. 31, 2015
License Agreements [Abstract]
License Agreements	License Agreements The University of South Carolina Research Foundation, Corp. During 2007, the Company licensed certain technology from the University of South Carolina Research Foundation, Corp. (“USCRF”). The license gives the Company worldwide rights to use the technology as defined in the agreement. The agreement was amended in August 2013. The Company paid an annual licensing fee of $30,000 through 2008, $60,000 from 2009 through 2010, $62,000 from 2011 through 2012 and $122,000 in 2013. The Company is obligated to pay an annual licensing fee of $120,000 thereafter as long as the agreement remains in effect. Upon the achievement of certain defined product development milestones for diabetic neuropathy or hyperlipidemia, the Company would be obligated to make up to $6.1 million of payments to USCRF. The Company will be obligated to pay USCRF a one-time fee of $35,000 upon execution of a sublicense and would pay to USCRF 25% of any non-royalty sublicense payments received from a sub-licensee. The term of the agreement expires on the expiration of the underlying USCRF patents. The Company can terminate the license at any time upon three months prior written notice to USCRF. As of December 31, 2015, no development milestones have been paid or accrued nor does the Company expect to achieve any development milestones during the next few years. The Company paid $120,000 for each of the years ended December 31, 2015 and 2014, respectively, for annual licensing fees due under this agreement. In connection with the Company's plan to pause the clinical program of oral Pyridorin for the treatment of diabetic nephropathy (See note 13), the Company has provided written notice to USCRF to terminate this license agreement on February 26, 2016. Vanderbilt University During 2006, the Company entered into a licensing agreement with Vanderbilt University (“Vanderbilt”) for the rights to use certain technology. The agreement, as amended, requires the Company to make milestone payments totaling approximately $1.1 million in the event certain defined events occur. Should the Company successfully develop a product using the licensed technology, Vanderbilt will be due royalties based on net sales at a rate of 5% . The Company must also pay Vanderbilt 25% of non‑royalty sub‑licensee payments received from a sub‑licensee. Annual minimum royalties due under the licensing agreement are $10,000 and will increase to $25,000 when a claim in the licensed patent rights is issued in a major market country, as defined. The licensing agreement expires when the underlying patents to the licensed technology expire. The Company may terminate the agreement upon sixty days written notice to Vanderbilt. Certain milestones can be paid in stock or are creditable against future royalties due based on net sales. The Company paid $75,000 and $0 for the years ended December 31, 2015 and 2014, respectively, for milestone payments due under this agreement. The University of Kansas Medical Center Research Institute, Inc. During 2007, the Company received rights to certain technology licensed from the University of Kansas Medical Center Research Institute, Inc. ("KUMC") to the Company. The license gives the Company worldwide royalty-free rights to use certain technology. Upon the achievement of certain defined product development milestones, the Company would be obligated to make up to $225,000 of payments to KUMC. As of December 31, 2015 and 2014, no milestones have been paid or accrued. The term of the agreement expires on the expiration of the underlying KUMC patents or November 2018, whichever occurs last. The Company can terminate the agreement with 90 days notice. BioStratum, Inc. During 2007, the Company entered into a grant‑back license agreement with BioStratum, Inc. ("BioStratum"), as part of our acquisition of certain of BioStratum’s assets, including certain patent rights. The license grant to BioStratum was made solely to enable BioStratum to exercise its rights and perform its obligations pursuant to a license agreement with Kowa Company, Ltd. ("Kowa") pursuant to which BioStratum granted Kowa an exclusive license (the "Kowa Agreement") to manufacture and use licensed products in Japan, Taiwan, Korea, and China. The Kowa Agreement was terminated by Kowa on December 5, 2007. BioStratum did not exercise its option to assume Kowa's rights under the Kowa agreement. Therefore, the grant-back license agreement automatically terminated on January 15, 2008. However, the grant-back license agreement expressly states that the Company must have the written consent of BioStratum to grant licenses to the manufacture and use licensed products in Japan, Taiwan, Korea and China (the "Surviving Provision"). On June 22, 2015, the Company entered into a termination agreement with BioStratum ("Termination Agreement") to terminate this Surviving Provision under the grant-back license agreement. The Company paid $35,000 in connection with the execution of this Termination Agreement.

Convertible Notes Payable

Convertible Notes Payable	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Convertible Notes Payable	Convertible Notes Payable On February 14, 2014, in connection with the closing of the Company’s IPO, $7.9 million of convertible promissory notes and $728,000 of accrued interest were converted into 1,197,289 shares of common stock. Interest expense for the years ended December 31, 2015 and 2014 relating to the notes was approximately $0 and $78,000 , respectively. Term Loan On November 20, 2014, the Company entered into a Loan and Security Agreement (the "Loan Agreement") with East West Bank ("East West") for a term loan (the “Initial Term Loan”) with an aggregate principal amount of $7.0 million and, subject to the terms and conditions set forth in the agreement, a second term loan (the “Second Term Loan”) with an aggregate principal amount of $5.0 million . Each term loan shall accrue interest at a rate of 2.25% per annum plus the greater of 3.25% or the current prime rate. As of December 31, 2015 the interest rate on the loan was 5.75% . As security for its obligations under the Loan Agreement, the Company granted the East West a lien on substantially all of its assets, including owned and licensed intellectual property. The Loan Agreement contains customary representations and warranties and customary affirmative and negative covenants, including, among others, covenants that limit or restrict the Company's ability to incur indebtedness, grant liens, merge or consolidate, dispose of assets, make investments, make acquisitions, enter into certain transactions with affiliates, pay dividends or make distributions, or repurchase stock, in each case subject to customary exceptions for a loan facility of this size and type. In addition, the Loan Agreement contains customary events of default that entitle East West to cause any or all of our indebtedness under the Loan Agreement to become immediately due and payable. The events of default include, among others, non-payment, inaccuracy of representations and warranties, covenant defaults, the occurrence of a material adverse effect (as defined in the Loan Agreement), cross-default to material agreements, cross-default to material indebtedness, bankruptcy and insolvency, material judgment defaults, discontinuation of the Phase 3 Pyridorin trial and defaults related to certain actions taken against the us by the FDA or other equivalent governmental authority. On November 20, 2014, the bank funded the Initial Term Loan, which matures on October 1, 2018. Interest only payments are due during the first twelve months of the Initial Term Loan (the “Interest Only Term”) and beginning on November 1, 2015, the Company is required to make thirty-six ( 36 ) equal monthly payments of principal and interest. The Company paid a $120,000 facility fee which was recorded as a debt discount to be amortized as interest expense over the term of the loan using the effective interest rate method. At the Company’s option, the Company could have borrowed the Second Term Loan on or before May 29, 2015, if the Company had met certain clinical milestones. In January 2015, the Company made a proposal to East West requesting additional borrowing under the Second Term Loan. As of the date hereof, the Company has not met the clinical milestones for the Second Term Loan and no additional borrowing was granted under the Second Term Loan. The Company may prepay each term loan in full with no prepayment penalty. Upon payment of the final monthly installment of the loan, or the remaining balance in the case of a prepayment, the Company would pay an end-of-term fee of approximately $60,000 . In connection with the Initial Term Loan, the Company issued warrants to purchase an aggregate of 56,603 shares of the Company's common stock at an exercise price of $ 4.24 per share. The warrants are immediately exercisable and will expire on November 20, 2021. The Company determined the fair value of the warrants to be $ 192,450 using the Black-Scholes pricing model and recorded the warrants as a debt discount to be amortized as interest expense over the term of the Notes using the effective interest rate method. The Company also paid $50,000 in debt issuance costs, which were capitalized as a deferred asset and are being amortized over the expected remaining life of the loan using the effective interest method. The Company recognized $0.6 million and $62,000 in interest expense related to the term loan, including the amortization of the warrants, for the years ended December 31, 2015 and 2014, respectively. As of December 31, 2015 and 2014, the Company was in compliance with all financial and non-financial covenants under this Loan Agreement. The following represents the outstanding principal balances, carrying amounts and maturities of notes payable as of December 31, 2015 (in thousands) : Amortization of Accrued Carrying Value Principal Value Debt Discount Interest of Note Payable 2016 $ 2,333 $ (101 ) $ 32 $ 2,264 2017 2,334 (57 ) 21 2,298 2018 1,944 (14 ) 10 1,940 $ 6,611 $ (172 ) $ 63 $ 6,502 Less current portion 2,264 Long-term note payable, net of discount $ 4,238 On February 23, 2016, the Company paid off all amounts outstanding under the term loan, accrued interest expense and an end-of-term fee, totaling approximately $ 6.3 million .

Term Loan

Term Loan	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Term Loan	Convertible Notes Payable On February 14, 2014, in connection with the closing of the Company’s IPO, $7.9 million of convertible promissory notes and $728,000 of accrued interest were converted into 1,197,289 shares of common stock. Interest expense for the years ended December 31, 2015 and 2014 relating to the notes was approximately $0 and $78,000 , respectively. Term Loan On November 20, 2014, the Company entered into a Loan and Security Agreement (the "Loan Agreement") with East West Bank ("East West") for a term loan (the “Initial Term Loan”) with an aggregate principal amount of $7.0 million and, subject to the terms and conditions set forth in the agreement, a second term loan (the “Second Term Loan”) with an aggregate principal amount of $5.0 million . Each term loan shall accrue interest at a rate of 2.25% per annum plus the greater of 3.25% or the current prime rate. As of December 31, 2015 the interest rate on the loan was 5.75% . As security for its obligations under the Loan Agreement, the Company granted the East West a lien on substantially all of its assets, including owned and licensed intellectual property. The Loan Agreement contains customary representations and warranties and customary affirmative and negative covenants, including, among others, covenants that limit or restrict the Company's ability to incur indebtedness, grant liens, merge or consolidate, dispose of assets, make investments, make acquisitions, enter into certain transactions with affiliates, pay dividends or make distributions, or repurchase stock, in each case subject to customary exceptions for a loan facility of this size and type. In addition, the Loan Agreement contains customary events of default that entitle East West to cause any or all of our indebtedness under the Loan Agreement to become immediately due and payable. The events of default include, among others, non-payment, inaccuracy of representations and warranties, covenant defaults, the occurrence of a material adverse effect (as defined in the Loan Agreement), cross-default to material agreements, cross-default to material indebtedness, bankruptcy and insolvency, material judgment defaults, discontinuation of the Phase 3 Pyridorin trial and defaults related to certain actions taken against the us by the FDA or other equivalent governmental authority. On November 20, 2014, the bank funded the Initial Term Loan, which matures on October 1, 2018. Interest only payments are due during the first twelve months of the Initial Term Loan (the “Interest Only Term”) and beginning on November 1, 2015, the Company is required to make thirty-six ( 36 ) equal monthly payments of principal and interest. The Company paid a $120,000 facility fee which was recorded as a debt discount to be amortized as interest expense over the term of the loan using the effective interest rate method. At the Company’s option, the Company could have borrowed the Second Term Loan on or before May 29, 2015, if the Company had met certain clinical milestones. In January 2015, the Company made a proposal to East West requesting additional borrowing under the Second Term Loan. As of the date hereof, the Company has not met the clinical milestones for the Second Term Loan and no additional borrowing was granted under the Second Term Loan. The Company may prepay each term loan in full with no prepayment penalty. Upon payment of the final monthly installment of the loan, or the remaining balance in the case of a prepayment, the Company would pay an end-of-term fee of approximately $60,000 . In connection with the Initial Term Loan, the Company issued warrants to purchase an aggregate of 56,603 shares of the Company's common stock at an exercise price of $ 4.24 per share. The warrants are immediately exercisable and will expire on November 20, 2021. The Company determined the fair value of the warrants to be $ 192,450 using the Black-Scholes pricing model and recorded the warrants as a debt discount to be amortized as interest expense over the term of the Notes using the effective interest rate method. The Company also paid $50,000 in debt issuance costs, which were capitalized as a deferred asset and are being amortized over the expected remaining life of the loan using the effective interest method. The Company recognized $0.6 million and $62,000 in interest expense related to the term loan, including the amortization of the warrants, for the years ended December 31, 2015 and 2014, respectively. As of December 31, 2015 and 2014, the Company was in compliance with all financial and non-financial covenants under this Loan Agreement. The following represents the outstanding principal balances, carrying amounts and maturities of notes payable as of December 31, 2015 (in thousands) : Amortization of Accrued Carrying Value Principal Value Debt Discount Interest of Note Payable 2016 $ 2,333 $ (101 ) $ 32 $ 2,264 2017 2,334 (57 ) 21 2,298 2018 1,944 (14 ) 10 1,940 $ 6,611 $ (172 ) $ 63 $ 6,502 Less current portion 2,264 Long-term note payable, net of discount $ 4,238 On February 23, 2016, the Company paid off all amounts outstanding under the term loan, accrued interest expense and an end-of-term fee, totaling approximately $ 6.3 million .

Stockholders' equity (deficit)

Stockholders' equity (deficit)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Stockholders' equity (deficit)	Stockholders' equity (deficit) Series A Preferred Stock In connection with the completion of the IPO, 3,644,354 shares of common stock were issued for the conversion of all outstanding shares of the Company’s Series A Preferred stock. Warrants On January 16, 2014, an agreement was reached among the Company’s significant shareholders to cancel warrants held by its majority shareholder, Care Capital Investments III, LP, together with its affiliates (collectively, Care Capital), and by funds affiliated with Rho Venture Partners (Rho). Pursuant to this agreement, an aggregate of 593,589 shares of the Company’s common stock were issued to Care Capital and Rho concurrently with the completion of the Company’s IPO in return for cancelling the warrants. In connection with the cancellation of the warrants, the Company settled the preferred stock warrant liability on its balance sheet. On February 10, 2014, the Company, in connection with the IPO, issued the underwriter warrants to purchase up to 62,000 shares of common stock. The warrants are exercisable at any time commencing one year from the effective date of the Company’s IPO. The warrants are exercisable at a price of $15.00 per share and expire on February 10, 2018. On November 20, 2014, the Company, in connection with the issuance of a term loan, issued warrants to a lender to purchase up to an aggregate of 56,603 shares of the Company's common stock at an exercise price of $4.24 per share. The warrants are immediately exercisable and will expire on November 20, 2021. On July 22, 2015, the Company, in connection with the sale of common stock, issued warrants to purchase 1,725,000 shares of the Company's common stock at an exercise price of $6.25 per share. The warrants are immediately exercisable and expire on July 22, 2020. On November 6, 2015, the Company, in connection with the sale of common stock, issued the following warrants to purchase common stock: Description Warrants Exercise Price Date Exercisable Expiration Term Series A Warrants 1,617,647 $3.56 May 6, 2016 November 6, 2020 5 years Series B Warrants 2,156,863 $3.56 May 6, 2016 November 7, 2016 12 months + 1 day Series C Warrants 2,156,863 $3.56 May 6, 2016 May 6, 2017 18 months Series D Warrants 2,156,863 $3.56 May 6, 2016 July 6, 2016 8 months Total 8,088,236 In addition, the Company issued warrants to purchase up to an aggregate of 107,843 share of common stock with the same terms as the Series A Warrants to the placement agent for the transaction. As of December 31, 2015, the following warrants to purchase common stock were outstanding: Exercise Issuance Date Shares Price Expiration 2/10/2014 62,000 $ 15.00 2/10/2018 11/20/2014 56,603 $ 4.24 11/20/2021 7/22/2015 1,725,000 $ 6.25 7/22/2020 11/6/2015 2,156,863 $ 3.56 7/6/2016 11/6/2015 2,156,863 $ 3.56 11/7/2016 11/6/2015 2,156,863 $ 3.56 5/6/2017 11/6/2015 1,725,490 $ 3.56 11/6/2021 Total warrants outstanding 10,039,682 Common Stock On February 14, 2014, the Company filed an Amended and Restated Certificate of Incorporation which authorizes the issuance of 100,000,000 shares of common stock, and 5,000,000 shares of undesignated preferred stock. Public Offering On July 22, 2015, the Company completed a public offering of common stock and sold 1,500,000 shares of common stock and warrants to purchase common stock at a price of $5.00 per share and accompanying warrant for total gross proceeds of $7.5 million. Concurrent with closing of the offering, the underwriters exercised their option to purchase 225,000 warrants for $0.01 per share for total gross proceeds to the Company of $2,250 . On July 31, 2015, the underwriters partially exercised their over-allotment to purchase 112,500 shares of common stock at $4.99 per share for total gross proceeds of $561,375 . Total net proceeds from the public offering were approximately $7.1 million after deducting underwriting discounts, commissions and offering expenses of approximately $1.0 million. At Market Issuance Sales Agreement On August 7, 2015, the Company entered into an At Market Issuance Sales Agreement (the “Agreement”), with MLV & Co. LLC, as sales agent (“MLV”), pursuant to which the Company may offer and sell, from time to time, through MLV, shares of the Company’s common stock, (the “ATM Shares”), up to an aggregate offering price of $18.0 million. The Company intends to use the net proceeds received from any issuance of ATM shares under the Agreement for working capital and general corporate purposes. Under the Agreement, MLV may sell the ATM Shares by methods deemed to be an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended (the “Securities Act”), including sales made directly on the NASDAQ Capital Market, on any other existing trading market for the ATM Shares or to or through a market maker. In addition, under the Agreement, MLV may sell the Shares by any other method permitted by law, including in privately negotiated transactions. Subject to the terms and conditions of the Agreement, MLV will use commercially reasonable efforts, consistent with its normal trading and sales practices and applicable state and federal law, rules and regulations and the rules of the NASDAQ Capital Market, to sell the ATM Shares from time to time, based upon the Company's instructions (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company is not obligated to make any sales of the ATM Shares under the Agreement. The offering of ATM Shares pursuant to the Agreement will terminate upon the earlier of (1) the sale of all of the ATM Shares subject to the Agreement or (2) the termination of the Agreement by MLV or the Company. The Company will pay MLV a commission of up to 3.0% of the gross sales price per ATM Share sold and has agreed to provide MLV with customary indemnification and contribution rights. As of December 31, 2015, the Company had sold 308,541 ATM Shares of common stock at an average sales price of $3.92 per ATM Share for total net proceeds of approximately $1.1 million after deducting discounts and commissions and estimated offering expenses of approximately $98,000 . PIPE Offering On November 6, 2015, the Company sold 2,156,863 shares of common stock pursuant to a securities purchase agreement to certain institutional investors ("PIPE offering") at a purchase price of $2.55 per share for total gross proceeds of approximately $5.5 million . As part of this PIPE offering, the Company issued warrants to purchase 8.1 million shares of its common stock at $3.56 per share. Other Common Stock Issuances During 2015, the Company issued 6,000 shares of common stock to its chief executive officer for restricted stock units that vested during the year. Shares Reserved for Future Issuance As of December 31, 2015, the Company had 12,946,018 shares of common stock outstanding. The Company has reserved shares of common stock for future issuance as of December 31, 2015 as follows: Stock options outstanding 1,542,732 Shares available for grant under stock option plans 49,401 Restricted stock units 891,617 Common stock warrants 10,039,682 Total shares reserved for future issuance 12,523,432 Stock Based Compensation In 2005, the Company adopted the NephroGenex, Inc. 2005 Stock Option Plan. On May 15, 2014, the 2005 Stock Option Plan, was amended and restated to the 2007 Equity Incentive Plan (the “Plan”). The amendment authorized an increase of 673,923 shares and provided for the granting of up to 1,283,226 shares of common stock to employees and consultants of the Company in the form of incentive and nonqualified stock options and shares of restricted stock. On March 24, 2015, the Company’s Board of Directors adopted, and stockholders subsequently approved, an amendment to the Company's Amended and Restated 2007 Equity Incentive Plan, as amended (the “Stock Plan”) to increase the number of shares authorized for issuance of awards under the Stock Plan from 1,283,226 to an aggregate of 2,483,226 shares of common stock. As of December 31, 2015, there were 49,401 shares available for issuance from the Stock Plan. Stock Options The table below summarizes stock option activity for the years ended December 31, 2015 and 2014. Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Outstanding as of December 31, 2013 563,453 $ 1.18 Granted 712,204 6.60 Exercised — — Expired — — Forfeited (3,076 ) 11.90 Outstanding as of December 31, 2014 1,272,581 4.19 Granted 467,183 5.04 Exercised — — Expired (4,865 ) 15.20 Forfeited (192,167 ) 5.23 Outstanding as of December 31, 2015 1,542,732 $ 4.28 7.5 Exercisable as of December 31, 2015 817,002 $ 3.23 5.3 During the years ended December 31, 2015 and 2014, the Company’s Board of Directors granted stock options of 467,183 and 712,204 , respectively to employees, a non-employee consultant and Directors of the Company with a weighted average fair value of $3.54 and $5.40 per share, respectively. The stock options vest based on terms in the stock option agreements (generally over four years) and are exercisable after they have been granted for up to ten years from the date of grant. The weighted-average assumptions used in the Black-Scholes valuation model for stock option awards granted during the years ended December 31, 2015 and 2014 are shown in the table below. 2015 2014 Expected volatility 99.69 % 88.29 % Expected dividends — — Expected life in years 6.0 6.5 Risk-free interest rate 1.75 % 1.98 % The Company determines the options’ life based upon the use of the simplified method. As a newly public company, sufficient history to estimate the volatility and dividend yield of our common stock is not available. The Company uses a pool of comparable companies as a basis for the expected volatility assumption and dividend yield. The Company intends to continue to consistently apply this process using the comparable companies until sufficient amount of historical information becomes available. The risk free interest rate is based upon the yield of an applicable Treasury instrument. In accounting for stock options to non-employees, the fair value of services related to the options granted are generally recorded as an expense as these services are provided to the Company over the relating service periods. The Company re-measures any unvested, non-employee options to fair value at the end of each reporting period using the Black-Scholes pricing model. At December 31, 2015, the aggregate intrinsic value of options outstanding was $0.4 million . The aggregate intrinsic value of options outstanding as of December 31, 2015 represents the pretax value (the Company's closing market price of $1.60 per share on December 31, 2015, less the exercise price per share, times the number of in-the-money options) that would have been received by all option holders had they exercised their options at the end of the period. No options were exercised during the years ended December 31, 2015 or 2014. Restricted Stock Units (RSU) In November 2013, the Company issued 24,000 Restricted Stock Units (RSU) to its CEO in connection with his employment agreement. The RSU represent the right to receive shares of common stock, subject to the terms and conditions of a restricted stock unit agreement and grant notice and were not issued under the Plan. The RSU’s are subject to time based vesting with 25% of the RSU’s vesting on October 21, 2014 and the remaining 75% are vesting in equal monthly installments on the 1 st day of each calendar month beginning November 1, 2014. As of December 31, 2015, the Company had issued 13,000 shares of common stock for RSU's that had vested. In November 2015, the Company issued Restricted Stock Units (RSU) to its named executive officers. The RSU represent the right to receive shares of common stock, subject to the terms and conditions of a restricted stock unit agreement (the "agreement") and the Plan. The RSUs are subject to time based vesting in equal quarterly installments on the first day of each calendar quarter, beginning on January 1, 2016 and continuing for 11 additional quarters thereafter, provided that the applicable officers continues to provide services to the Company. Subsequently, these named executive officers elected to defer the receipt of shares of common stock in connection with the issuance of these RSUs until the separation from services from the Company or change in control defined in the agreement. Restricted stock units will be settled through the issuance of an equivalent number of shares of our common stock and are equity classified. The Company measures the fair value of grants of restricted stock units based on the closing market price of a share of its common stock on the date of grant. The following table summarizes the activity related to restricted stock units during 2015: Units Weighted Average Grant Date Fair Value Unvested at January 1 17,000 $ 4.55 Units granted 880,617 $ 2.31 Units vested (6,000 ) $ 4.55 Units forfeited — Unvested at December 31 891,617 $ 2.34 As of December 31, 2015, there was $4.6 million of unrecognized compensation expense related to unvested stock options and RSUs, which is expected to be recognized over a weighted average period of 1.42 years. The Company recognized non-cash stock-based compensation expense in its research and development and general and administrative expenses as follows: Year Ended December 31, (in thousands) 2015 2014 Research and development $ 335 $ 130 General and administrative 1,140 821 Total $ 1,475 $ 951

Retirement Savings Plan

Retirement Savings Plan	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Retirement Savings Plan	Retirement Savings Plan The Company provides a qualified 401(k) savings plan for its employees. All employees are eligible to participate, provided they meet the requirements of the plan. The Company provides a contribution on the first 3% of an employee's eligible salary subject to statutory limitations as prescribed by law. For the years ended December 31, 2015 and 2014, the Company recorded $50,000 and $48,000 of expense for 401(k) contributions, respectively.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Prior to June 30, 2014, the Company reimbursed Care Capital, LLC (“Care”), an affiliate of the majority shareholder of the Company, for services of a Care employee and reimbursed Care for such personnel services incurred by Care on behalf of the Company. Total expense recognized in operating results for the years ended December 31, 2015 and 2014 in connection with services provided by Care was $0 and $70,000 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company recognized deferred tax liabilities and assets for the expected future tax consequences of events that have been recognized differently between the financial statements and tax returns. Under this method, deferred tax liabilities and assets are determined based on the difference between the financial statement carrying amounts and tax basis of liabilities and assets using enacted tax rates and laws in effect in the years in which the differences are expected to reverse. Deferred tax assets are evaluated for realization based on a more‑likely‑than‑not criteria in determining if a valuation allowance should be provided. There was no income tax provision for the years ended December 31, 2015 and 2014. The components of the Company’s deferred tax assets at December 31, 2015 and 2014 are as follows: (in thousands) 2015 2014 Net operating loss carry forwards $ 14,841 $ 11,044 Stock based compensation 749 357 Tax credits 1,720 1,516 Depreciation (2 ) 1 Amortization 10,388 6,392 Accrued compensation 28 — Accrued expenses 9 4 Accrued interest — 12 Deferred tax assets 27,733 19,326 Less: valuation allowance (27,733 ) (19,326 ) Net deferred tax asset $ — $ — The Company’s valuation allowance increased by $8.4 million and $5.2 million during the years ended December 31, 2015 and 2014, respectively. The reconciliation between the Company’s effective tax rate and the federal statutory rate for the years ended December 31, 2015 and 2014 are as follows : 2015 2014 Federal statutory rate (34.00 )% (34.00 )% State income taxes (2.80 )% 0.73 % Valuation allowance (36.80 )% 33.27 % Effective tax rate — % — % As of December 31, 2015, the Company had approximately $41.9 million of Federal net operating losses that will begin to expire in 2024 and approximately $22.4 million of State net operating losses that will begin to expire in 2026. As of December 31, 2015, the Company has research and development credit carryovers for Federal and New Jersey of approximately $1.5 million and $189,000 , respectively; these will begin to expire in 2024 for federal and 2016 for New Jersey tax purposes. The Internal Revenue Code (“IRC”) limits the amounts of net operating loss carryforwards that a company may use in any one year in the event of certain cumulative changes in ownership over a three‑year period as described in Section 382 of the IRC. The Company has not performed a detailed analysis to determine whether an ownership change has occurred. Such a change of ownership could limit the utilization of the net operating losses, and could be triggered by subsequent sales of securities by the Company or its stockholders. The Company did not have a liability related to unrecognized tax benefits as of December 31, 2015 or 2014. The Company records interest accrued and penalties related to unrecognized tax benefits within the income tax expense. The Company had not accrued any interest or penalties related to unrecognized benefits. The Company is no longer subject to federal income tax assessment for years before 2012 and for years before 2011 for New Jersey income tax purposes. However, since the Company has incurred net operating losses in every year since inception, all of its income tax returns are subject to examination and adjustments by the Internal Revenue Service for at least three years following the year in which the tax attributes are utilized. The Company does not believe that there will be a material change in its unrecognized tax positions over the next twelve months. There is no amount of unrecognized tax benefit that, if recognized, would affect the effective tax rate.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments	Commitments Lease On September 12, 2014, the Company entered into an agreement to lease office space at 3200 Beechleaf Court, Raleigh, North Carolina for the period December 1, 2014 through May 31, 2020. These premises will serve as the Company's corporate headquarters. The lease provides for abatement of rent during certain periods and escalating rent payments during the lease term. The Company records rent expense on a straight-line basis over the life of the lease. The following is a schedule of future non-cancellable minimum lease payments for operating leases at December 31, 2015 (in thousands): Year 2016 $ 118 2017 122 2018 125 2019 129 2020 55 $ 549 Rent expense was approximately $115,000 and $62,000 for the years ended December 31, 2015 and 2014, respectively. Legal Contingencies The Company is subject to claims and assessments from time to time in the ordinary course of business. The Company's management does not believe that any such matters, individually or in the aggregate, will have a material adverse effect on the Company's business, financial conditions, results of operations or cash flows. Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnification. The Company's exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but that have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. The Company may, however, record charges in the future as a result of these indemnification obligations. In accordance with its Amended and Restated Certificate of Incorporation and Bylaws, the Company has indemnification obligations to its directors, and has the authority to indemnify its officers and employees, for certain events or occurrences, subject to certain limits, while they are serving at the Company's request in such capacity. There have been no claims to date, and the Company has director and officer insurance that enables it to recover a portion of any amounts paid for future potential claims. In addition to the indemnification provided for in its Certificate of Incorporation and Bylaws, the Company has also entered into separate indemnification agreements with each of its directors, which agreements provide such directors with indemnification rights under certain circumstances.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Recent Developments On February 24, 2016, the Company announced that its Board of Directors (the "BOD") has made a determination to pause the clinical program of the Company's product candidate oral Pyridorin for the treatment of diabetic nephropathy, effect a restructuring of its operations and implement a strategic transaction. The BOD made this determination in light of the remaining trial costs, the Company's cash balance and condition of the capital markets. Concurrently, the BOD retained MTS Health Partners, L.P. to act as financial adviser in connection with the Company's exploration of potential business alternatives and the Company implemented a workforce reduction plan. The workforce reduction eliminated approximately five positions throughout the Company, impacting primarily positions within its research and development function. The Company anticipates recording approximately $ 175,000 of restructuring charges during the first quarter of 2016 covering severance, related benefits and other costs. In connection with the exploration of potential business alternatives, the Company also paid off all amounts outstanding under the term loan, accrued interest expense and an end-of-term fee, totaling approximately $ 6.3 million .

Significant Accounting Polici21

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).
Liquidity	Going Concern The Company's financial statements have been prepared on a basis which assumes that the Company will continue as a going concern and which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. The Company has incurred losses since its inception, expects to incur additional costs and requires additional capital to continue as a going concern. As a result, the Company will require additional funds and will continue to seek private or public equity to meet its capital requirements. Even if the Company does not have an immediate need for additional cash, it may seek access to the private or public equity markets if and when conditions are favorable. If such funds are not available, management may need to reassess its business plans. There is no assurance that such additional funds will be available for the Company to finance its operations on acceptable terms, if at all. As a result of the announcement in February 2016, the Company determined to suspend all development and clinical trials activities due to the lack of financial resources and to seek other potential business alternatives that may be available.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Warranty Liability	Warrant Liability Certain warrants to purchase the Company’s capital stock had historically been classified as liabilities and were recorded at estimated fair value. At each reporting period, any change in fair value of the freestanding warrants was recorded as other (expense) income. The Company recorded $140,000 as other expense as as a result of the change in fair value of the preferred stock warrant liability for the years ended December 31, 2014. The preferred stock warrant liability was settled upon the closing of the IPO.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents.
Restricted Cash	Restricted Cash Restricted cash consists of deposits held by a financial institution as collateral for the Company's corporate credit card.
Investments	Investments The Company invests in money market funds and certificates of deposits and considers all investments purchased with original maturity dates greater than three months and less than one year to be short-term investments. Those investments with original maturity dates greater than one year at each balance sheet date are considered to be long-term investments. As of December 31, 2015, all investments were classified as available-for-sale and had original maturity dates less than one year. These investments are carried at estimated fair value with unrealized gains and losses included in stockholders' equity. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income.
Concentration of Credit Risk	Concentration of Credit Risk The Company invests its available cash balances in bank deposits, money market funds and certificates of deposit. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. Additionally, the Company has established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.
Property and Equipment	Property and Equipment Property and equipment consists of furniture, fixtures and computers. Property and equipment are carried at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the respective asset's estimated useful life. Maintenance and repairs that do not improve or extend the life of assets are expensed as incurred. When an asset is retired or disposed of, the cost and related accumulated depreciation are removed from the accounts and any resulting gains or losses are reflected within the statement of operations. Useful lives generally range from three to seven years.
Fair value of Financial Instruments	Fair Value of Financial Instruments As of December 31, 2015, financial instruments consist of cash and cash equivalents, short-term investments, a term loan, accounts receivable and accounts payable. The Company defines fair value (“FV”) as the price that would be received to sell an asset or paid to transfer a liability ("the exit price") in an orderly transaction between market participants at the measurement date. The FV hierarchy for inputs maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. The Company uses the following hierarchy of inputs to measure FV: • Level 1: Quoted prices in active markets for identical assets or liabilities; • Level 2: Inputs, other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities in active markets; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and • Level 3: Unobservable inputs that are supported by little or no market activity, which require the reporting entity to develop its own assumptions. The Company values investments using the most observable inputs available that are current as of the measurement date and classifies them according to the lowest level of inputs used. Observable inputs are inputs that market participants would use in pricing the asset or liability developed from market data obtained from independent sources. Unobservable inputs are those which reflect the Company’s judgment concerning the assumptions that market participants would use in pricing the asset or liability developed from the best information available under the circumstances. The Company targets investments principally in Level 1 and Level 2 cash equivalents and financial instruments and records them at FV. The Company did not rely on Level 3 inputs for the valuation of any investments at December 31, 2015 or December 31, 2014. The Company expects that the carrying values of cash equivalents will approximate FV because of their short maturities. The Company classifies as Level 2 investments in certificates of deposits and values them using the market approach based on significant other observable inputs including quoted prices in active markets for instruments that are similar or quoted prices in markets that are not traded on a daily basis for identical or similar instruments.
Debt Issuance Cost	Debt Issuance Costs Debt issuance costs represent legal and other direct costs related to the Company's outstanding loan. These costs are recorded as an asset on the accompanying balance sheets and are being amortized to interest expense utilizing the effective interest method through the earliest date at which the Company can be required to repay the notes.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses include personnel costs associated with research and development activities including non-cash share-based compensation, costs for third-party contractors to perform research, conduct clinical trials and manufacture drug supplies and materials. The Company accrues for costs incurred by external service providers, including contract research organizations and clinical investigators, based on its estimates of service performed and costs incurred. These estimates include the level of services performed by the third parties, patient enrollment in clinical trials, administrative costs incurred by the third parties, and other indicators of the services completed. Based on the timing of amounts invoiced by service providers, the Company may also record payments made to those providers as prepaid expenses that will be recognized as expense in future periods as the related services are rendered.
Stock-Based Compensation	Stock-Based Compensation The Company estimates the FV of stock options and stock purchase rights using a Black-Scholes option valuation model which requires the input of highly subjective assumptions, including the option’s expected life and the price volatility of the underlying stock. The Company uses the simplified method for estimating the expected term as provided by the Securities and Exchange Commission's Staff Accounting Bulletin No. 107. The simplified method calculates the expected term as the average time-to-vesting and the contractual life of the options. The expected stock price volatility assumption was determined by examining the historical volatilities of a group of industry peers. The FV of each option grant is estimated on the date of grant using the Black-Scholes option valuation model, and the resulting FV is expensed using the straight-line attribution method over the vesting period, which is the same as the requisite service period. Restricted stock units are measured at the FV of the Company's common stock on the date of grant and expensed over the period of vesting, which is the same as the requisite service period using the straight-line attribution method. The Company has also granted stock options to non-employees. Grants to non-employees are accounted for in accordance with Accounting Standards Codification ("ASC") 505-50 Equity – Based Payments to Non-Employees. The Company determines the fair value of share based awards granted to nonemployees similar to the way fair value of awards are determined for employees except that certain assumptions used in the Black-Scholes option-pricing model, such as expected life of the option, may be different and the fair value of each award is adjusted at the end of each period for any change in fair value from the previous valuation until the award vests.
Recent Accounting Pronouncements	Recently Issued Accounting Pronouncements Occasionally, new accounting standards are issued or proposed by the Financial Accounting Standards Board (the “FASB”), or other standards-setting bodies that the Company adopts by the effective date specified within the standard. Unless otherwise discussed, standards that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption. I n August 2014, FASB issued Accounting Standards Update (“ASU”) No. 2014-15, “ Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” The amendments in this ASU are intended to define management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. Specifically, this ASU provides a definition of the term substantial doubt and requires an assessment for a period of one year after the date that the financial statements are issued (or available to be issued). It also requires certain disclosures when substantial doubt is alleviated as a result of consideration of management’s plans and requires an express statement and other disclosures when substantial doubt is not alleviated. The new standard will be effective for annual periods ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. We are currently evaluating the impact the adoption of this standard will have on the Company's financial statements and disclosures. In April 2015, the FASB issued ASU No. 2015-03, " Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs." The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this ASU. The new standard will be effective for reporting periods beginning after December 15, 2015, with early adoption permitted. The amendments should be applied on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new standard. We have not adopted this ASU as of December 31, 2015, but believe that the adoption of this ASU will not have a material impact on the Company's financial statements and related disclosures. In April 2015, the FASB issued ASU No. 2015-05, " Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement. " The amendments in this ASU provide guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The amendments do not change the accounting for a customer's accounting for service contracts. The new standard will be effective for annual periods ending after December 15, 2015, and interim periods thereafter, with early adoption permitted. We have not adopted this ASU as of December 31, 2015, but believe that the adoption of this ASU will not have a material impact on the Company's financial statements and related disclosures. In November 2015, the FASB issued ASU No. 2015-17, " Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes." This amendment requires deferred tax liabilities and assets to be classified as non-current in a classified statement of financial position, as opposed to separating the deferred tax liability and asset amounts into current and non-current amounts. The new standard will be effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods, with early adoption permitted. We are currently evaluating the impact the adoption of this standard will have on the Company's financial statements and disclosures.

Significant Accounting Polici22

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	The following table sets forth our financial instruments carried at FV within the ASC 820 hierarchy and using the lowest level of input as of December 31, 2014: Quoted Prices in Active Significant (in thousands) Markets Other Significant Balance For Identical Assets Observable Inputs Unobservable Inputs Assets: December 31, 2014 Level 1 Level 2 Level 3 Certificates of Deposit $ 16,765 $ — $ 16,765 $ — Total Assets $ 16,765 $ — $ 16,765 $ —

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the computation of basic and diluted net loss per share in thousands, except share and per share data: Year Ended December 31, 2015 2014 Numerator: Net loss $ (22,864 ) $ (16,820 ) Denominator: Weighted average common shares outstanding 10,005,451 7,827,519 Net loss per share- basic and diluted $ (2.29 ) $ (2.15 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows: 2015 2014 Common stock options 1,542,732 848,025 Restricted stock units 891,617 24,000 Common stock warrants 10,039,682 61,039

Balance Sheet Items (Tables)

Balance Sheet Items (Tables)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Available-for-sale Securities	The following table summarizes the Company's available for sale investments as of December 31, 2015 (in thousands): Maturity Amortized Unrealized Unrealized Estimated Short-term Investments (in years) Cost Gains Loss Fair Value Certificates of Deposit 1 or less $ 2,897 $ — $ (3 ) $ 2,894 Total Investments $ 2,897 $ — $ (3 ) $ 2,894 The following table summarizes the Company's available for sale investments as of December 31, 2014 (in thousands): Maturity Amortized Unrealized Unrealized Estimated Short-term Investments (in years) Cost Gains Loss Fair Value Certificates of Deposit 1 or less $ 14,706 $ — $ (8 ) $ 14,698 Total Investments $ 14,706 $ — $ (8 ) $ 14,698
Schedule of Plant and Equipment	As of December 31, 2015 and 2014 property and equipment were as follows (in thousands): Useful Life 2015 2014 Computer equipment 3-5 years $ 67 $ 54 Furniture and fixtures 7 years 66 66 Leasehold improvements 5.5 years 18 18 151 138 Less accumulated depreciation and amortization (113 ) (102 ) Property and equipment, net $ 38 $ 36
Schedule of Accrued Liabilities	As of December 31, 2015 and 2014 accrued liabilities were as follows (in thousands): 2015 2014 Accrued clinical trial expenses $ 2,432 $ 393 Accrued compensation 964 909 Other accruals 7 103 Total $ 3,403 $ 1,405

Term Loan (Tables)

Term Loan (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Schedule of Term Loan	The following represents the outstanding principal balances, carrying amounts and maturities of notes payable as of December 31, 2015 (in thousands) : Amortization of Accrued Carrying Value Principal Value Debt Discount Interest of Note Payable 2016 $ 2,333 $ (101 ) $ 32 $ 2,264 2017 2,334 (57 ) 21 2,298 2018 1,944 (14 ) 10 1,940 $ 6,611 $ (172 ) $ 63 $ 6,502 Less current portion 2,264 Long-term note payable, net of discount $ 4,238 On February 23, 2016, the Company paid off all amounts outstanding under the term loan, accrued interest expense and an end-of-term fee, totaling approximately $ 6.3 million .

Stockholders' equity (deficit)

Stockholders' equity (deficit) (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Schedule of warrants outstanding	As of December 31, 2015, the following warrants to purchase common stock were outstanding: Exercise Issuance Date Shares Price Expiration 2/10/2014 62,000 $ 15.00 2/10/2018 11/20/2014 56,603 $ 4.24 11/20/2021 7/22/2015 1,725,000 $ 6.25 7/22/2020 11/6/2015 2,156,863 $ 3.56 7/6/2016 11/6/2015 2,156,863 $ 3.56 11/7/2016 11/6/2015 2,156,863 $ 3.56 5/6/2017 11/6/2015 1,725,490 $ 3.56 11/6/2021 Total warrants outstanding 10,039,682
Schedule of reserved shares for future issuance	The Company has reserved shares of common stock for future issuance as of December 31, 2015 as follows: Stock options outstanding 1,542,732 Shares available for grant under stock option plans 49,401 Restricted stock units 891,617 Common stock warrants 10,039,682 Total shares reserved for future issuance 12,523,432
Schedule of stock option activity	The table below summarizes stock option activity for the years ended December 31, 2015 and 2014. Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Outstanding as of December 31, 2013 563,453 $ 1.18 Granted 712,204 6.60 Exercised — — Expired — — Forfeited (3,076 ) 11.90 Outstanding as of December 31, 2014 1,272,581 4.19 Granted 467,183 5.04 Exercised — — Expired (4,865 ) 15.20 Forfeited (192,167 ) 5.23 Outstanding as of December 31, 2015 1,542,732 $ 4.28 7.5 Exercisable as of December 31, 2015 817,002 $ 3.23 5.3
Schedule of stock option valuation assumptions	The weighted-average assumptions used in the Black-Scholes valuation model for stock option awards granted during the years ended December 31, 2015 and 2014 are shown in the table below. 2015 2014 Expected volatility 99.69 % 88.29 % Expected dividends — — Expected life in years 6.0 6.5 Risk-free interest rate 1.75 % 1.98 %
Schedule of share-based compensation	The Company recognized non-cash stock-based compensation expense in its research and development and general and administrative expenses as follows: Year Ended December 31, (in thousands) 2015 2014 Research and development $ 335 $ 130 General and administrative 1,140 821 Total $ 1,475 $ 951

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Deferred Tax Assets	The components of the Company’s deferred tax assets at December 31, 2015 and 2014 are as follows: (in thousands) 2015 2014 Net operating loss carry forwards $ 14,841 $ 11,044 Stock based compensation 749 357 Tax credits 1,720 1,516 Depreciation (2 ) 1 Amortization 10,388 6,392 Accrued compensation 28 — Accrued expenses 9 4 Accrued interest — 12 Deferred tax assets 27,733 19,326 Less: valuation allowance (27,733 ) (19,326 ) Net deferred tax asset $ — $ —
Schedule of Effective Income Tax Rate Reconciliation	The reconciliation between the Company’s effective tax rate and the federal statutory rate for the years ended December 31, 2015 and 2014 are as follows : 2015 2014 Federal statutory rate (34.00 )% (34.00 )% State income taxes (2.80 )% 0.73 % Valuation allowance (36.80 )% 33.27 % Effective tax rate — % — %

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Operating Lease Payments	The following is a schedule of future non-cancellable minimum lease payments for operating leases at December 31, 2015 (in thousands): Year 2016 $ 118 2017 122 2018 125 2019 129 2020 55 $ 549

Description of the Business a29

Description of the Business and Basis of Presentation (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (80,683)	$ (57,819)

Significant Accounting Polici30

Significant Accounting Policies - Reverse Stock Split and IPO (Details) $ / shares in Units, $ in Thousands	Jul. 31, 2015USD ($)	Jul. 22, 2015shares	Feb. 14, 2014USD ($)$ / sharesshares	Feb. 06, 2014	Jan. 16, 2014shares	Dec. 31, 2015USD ($)$ / shares	Dec. 31, 2014USD ($)
Class of Stock [Line Items]
Issuance of common stock at IPO (in shares)		1,500,000	3,100,000
Share price | $ / shares			$ 12			$ 1.60
Issuance of common stock at IPO | $			$ 33,400			$ 7,100	$ 33,433
Payment of initial public offering costs | $	$ 0		$ 3,800			$ 1,579	$ 3,737
Common Stock
Class of Stock [Line Items]
Reverse stock split description				1-for-6.5
Reverse stock split ratio				0.1538
Issuance of common stock for preferred stock (in shares)			3,644,354
Issuance of common stock for convertible notes and accrued interest (in shares)			1,197,289
Issuance of common stock for preferred stock warrant (in shares)			593,589		593,589

Significant Accounting Polici31

Significant Accounting Policies - Segment, PPE, and Debt Issuance Costs (Details)	12 Months Ended
	Dec. 31, 2015USD ($)segment	Dec. 31, 2014USD ($)
Accounting Policies [Abstract]
Number of operating segments | segment	1
Property, Plant and Equipment [Line Items]
Deferred issuance costs | $	$ 27,000	$ 48,000
Minimum
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	7 years

Significant Accounting Polici32

Significant Accounting Policies - Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of preferred stock warrants	$ 0	$ 140
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	7,142	16,765
Recurring | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	7,142	16,765
Recurring | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	0	0
Recurring | Fair Value, Inputs, Level 1 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	0	0
Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	7,142	16,765
Recurring | Fair Value, Inputs, Level 2 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	7,142	16,765
Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	0	0
Recurring | Fair Value, Inputs, Level 3 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 0	$ 0

Earnings Per Share - Basic and

Earnings Per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Numerator [Abstract]
Net loss	$ (22,864)	$ (16,820)
Denominator [Abstract]
Weighted average shares outstanding - basic and diluted (in shares)	10,005,451	7,827,519
Net loss per share - basic and diluted (in dollars per share)	$ (2.29)	$ (2.15)

Earnings Per Share - Antidiluti

Earnings Per Share - Antidilutive Securities (Details) - shares	Feb. 14, 2014	Jan. 16, 2014	Dec. 31, 2015	Dec. 31, 2014
Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Issuance of common stock for preferred stock (in shares)	3,644,354
Issuance of common stock for preferred stock warrant (in shares)	593,589	593,589
Common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per common share			1,542,732	848,025
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per common share			891,617	24,000
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per common share			10,039,682	61,039

Balance Sheet Items - Investmen

Balance Sheet Items - Investments in Equity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities [Abstract]
Amortized Cost	$ 2,897	$ 14,706
Unrealized Gains	0	0
Unrealized Loss	(3)	(8)
Short-term investments	2,894	14,698
Certificates of Deposit
Available-for-sale Securities [Abstract]
Amortized Cost	2,897	14,706
Unrealized Gains	0	0
Unrealized Loss	(3)	(8)
Short-term investments	$ 2,894	$ 14,698

Balance Sheet Items - Plant and

Balance Sheet Items - Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment, Net [Abstract]
Plant and equipment, gross	$ 151	$ 138
Less accumulated depreciation and amortization	(113)	(102)
Property and equipment, net	38	36
Depreciation	11	4
Computer equipment
Property, Plant and Equipment, Net [Abstract]
Plant and equipment, gross	$ 67	54
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	7 years
Property, Plant and Equipment, Net [Abstract]
Plant and equipment, gross	$ 66	66
Leasehold improvements
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	5 years 6 months
Property, Plant and Equipment, Net [Abstract]
Plant and equipment, gross	$ 18	$ 18
Minimum
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	3 years
Minimum | Computer equipment
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	7 years
Maximum | Computer equipment
Property, Plant and Equipment [Line Items]
Plant and equipment useful life	5 years

Balance Sheet Items - Accrued L

Balance Sheet Items - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities [Abstract]
Accrued clinical trial expenses	$ 2,432	$ 393
Accrued compensation	964	909
Other accruals	7	103
Total	$ 3,403	$ 1,405

License Agreements (Details)

License Agreements (Details) - USD ($)	Jun. 22, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2006	Dec. 31, 2007
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License costs		$ 15,306,000	$ 11,264,000
USCRF
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual licensing fee through 2008					$ 30,000
Annual licensing fee from 2009 through 2010					60,000
Annual licensing fee from 2011 through 2012					62,000
Annual licensing fee in 2013					122,000
Annual licensing fee thereafter					120,000
Potential milestone payments		6,100,000
Payments upon execution of a sub license		$ 35,000
Percentage of non-royalty based on sub-licensee payments received		25.00%
License costs			120,000
Vanderbilt
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments				$ 1,100,000
Percentage of non-royalty based on sub-licensee payments received				25.00%
Royalty payment percentage				5.00%
Annual minimum royalties due				$ 10,000
Potential minimum annual royalties due				$ 25,000
Collaborative Agreement, milestone payment		$ 75,000	$ 0
KUMC
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments					$ 225,000
Milestones paid or accrued		$ 0
BioStratum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement, termination payment	$ 35,000

Convertible Notes Payable (Deta

Convertible Notes Payable (Details) - USD ($) $ in Thousands	Feb. 14, 2014	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Interest expenses		$ 565	$ 140
Convertible Debt
Debt Instrument [Line Items]
Convertible promissory notes converted	$ 7,900
Convertible promissory notes accrued interest converted	$ 728
Shares issued for conversion of debt	1,197,289
Interest expenses		$ 0	$ 78

Term Loan Term Loan - Additiona

Term Loan Term Loan - Additional Information (Details)	Nov. 20, 2014USD ($)payment$ / sharesshares	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Jul. 22, 2015$ / sharesshares
Debt Instrument [Line Items]
Number of shares of stock to be acquired | shares	56,603			1,725,000
Warrants exercisable price per share (in dollars per share) | $ / shares	$ 4.24			$ 6.25
Fair value of warrants	$ 192,450
Payment of debt issuance costs		$ 0	$ 50,000
Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Variable rate floor	3.25%
Effective interest rate		5.75%
Payment of debt issuance costs	$ 50,000
Interest expense debt		$ 600,000	$ 62,000
Term Loan | Initial Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 7,000,000
Number of monthly payments | payment	36
Facility fee	$ 120,000
Payment terms balloon payment to be paid	60,000
Term Loan | Second Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 5,000,000

Term Loan - Schedule of Notes P

Term Loan - Schedule of Notes Payable (Details) - Term Loan $ in Thousands	Dec. 31, 2015USD ($)
Principal Value
2,016	$ 2,333
2,017	2,334
2,018	1,944
Total principal amount	6,611
Amortization of Debt Discount
2,016	(101)
2,017	(57)
2,018	(14)
Total amortization of debt discount	(172)
Accrued Interest [Abstract]
2,016	32
2,017	21
2,018	10
Interest	63
Carrying Value of Note Payable
2,016	2,264
2,017	2,298
2,018	1,940
Long-term debt	6,502
Less current portion	2,264
Long-term note payable, net of discount	$ 4,238

Stockholders' equity (deficit42

Stockholders' equity (deficit) - Series A Preferred Stock, Warrants, Common Stock (Details) - USD ($)	Nov. 06, 2015	Aug. 07, 2015	Jul. 31, 2015	Jul. 22, 2015	Feb. 14, 2014	Feb. 10, 2014	Jan. 16, 2014	Nov. 30, 2013	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Nov. 20, 2014
Class of Stock [Line Items]
Number of shares of stock to be acquired				1,725,000								56,603
Warrants exercisable price per share (in dollars per share)				$ 6.25								$ 4.24
Common stock, shares authorized					100,000,000					100,000,000	100,000,000
Preferred stock, shares authorized					5,000,000					5,000,000
Common stock warrants	8,088,236									10,039,682
Issuance of common stock at IPO (in shares)				1,500,000	3,100,000
Shares Issued, Price Per Share				$ 5
Sale of Stock, Maximum Shares Authorized to be Sold During Period				0
Proceeds from issuance of common stock and warrants			$ 0							$ 14,775,000	$ 37,200,000
Payment of initial public offering costs			$ 0		$ 3,800,000					$ 1,579,000	$ 3,737,000
Common Stock
Class of Stock [Line Items]
Issuance of common stock for preferred stock (in shares)					3,644,354
Issuance of common stock for preferred stock warrant (in shares)					593,589		593,589
Number of shares of stock to be acquired												56,603
Warrants exercisable price per share (in dollars per share)												$ 4.24
Underwriter | Common Stock
Class of Stock [Line Items]
Number of shares of stock to be acquired						62,000
Period from effective date of initial public offering until warrants are exercisable						1 year
Warrants exercisable price per share (in dollars per share)						$ 15
Warrant, issued February 2014 and expiring February 2018
Class of Stock [Line Items]
Warrants exercisable price per share (in dollars per share)										$ 15
Common stock warrants										62,000
Warrant, issued November 2014 and expiring November 2021
Class of Stock [Line Items]
Warrants exercisable price per share (in dollars per share)										$ 4.24
Common stock warrants										56,603
Warrant, issued July 2015 and expiring July 2020
Class of Stock [Line Items]
Warrants exercisable price per share (in dollars per share)										$ 6.25
Common stock warrants										1,725,000
Warrant, issued November 2015 and expiring July 2016
Class of Stock [Line Items]
Warrants exercisable price per share (in dollars per share)										$ 3.56
Common stock warrants										2,156,863
Warrant, issued November 2015 and expiring November 2016
Class of Stock [Line Items]
Warrants exercisable price per share (in dollars per share)										$ 3.56
Common stock warrants										2,156,863
Warrant, issued November 2015 and expiring May 2017
Class of Stock [Line Items]
Warrants exercisable price per share (in dollars per share)										$ 3.56
Common stock warrants										2,156,863
Warrant, issued November 2015 and expiring November 2021
Class of Stock [Line Items]
Warrants exercisable price per share (in dollars per share)										$ 3.56
Common stock warrants										1,725,490
Restricted stock units
Class of Stock [Line Items]
Number of award issued (in shares)										880,617
CEO | Restricted stock units
Class of Stock [Line Items]
Number of award issued (in shares)								24,000		6,000
Over-Allotment Option [Member]
Class of Stock [Line Items]
Issuance of common stock at IPO (in shares)			112,500
Shares Issued, Price Per Share			$ 4.99
Sale of Stock, Option to Purchase Shares				225,000
Sale of Stock, Option to Purchase Warrants, Price Per Warrant				$ 0.01
Proceeds from Issuance of Warrants				$ 2,250
Proceeds from Issuance of Common Stock			$ 561,375
PIPE Offering [Member]
Class of Stock [Line Items]
Number of shares of stock to be acquired	8,100,000
Warrants exercisable price per share (in dollars per share)	$ 3.56
Issuance of common stock at IPO (in shares)	2,156,863
Shares Issued, Price Per Share	$ 2.55
Proceeds from issuance of common stock and warrants	$ 5,500,000
Payment of initial public offering costs										$ 516,000
H.C. Wainwright & Co., LLC [Member]
Class of Stock [Line Items]
Number of shares of stock to be acquired	107,843
MLV & Co. LLC [Member]
Class of Stock [Line Items]
Issuance of common stock at IPO (in shares)									308,541
Shares Issued, Price Per Share									$ 3.92
Proceeds from Issuance of Common Stock									$ 1,100,000
Payment of initial public offering costs									$ 98,000	$ 98,000
Sale of Stock, Common Stock Maximum Offering Price		$ 18
Sale of Stock, Sales Agent Commission Rate		3.00%

Stockholders' equity (deficit43

Stockholders' equity (deficit) Stockholders' equity (deficit) - Schedule of Warrants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Nov. 06, 2015	Jul. 22, 2015	Nov. 20, 2014
Class of Warrant or Right [Line Items]
Common stock warrants	10,039,682	8,088,236
Warrants exercisable price per share (in dollars per share)			$ 6.25	$ 4.24
Series A Warrants
Class of Warrant or Right [Line Items]
Common stock warrants		1,617,647
Warrants exercisable price per share (in dollars per share)		$ 3.56
Class of warrant or right, term	5 years
Series B Warrants
Class of Warrant or Right [Line Items]
Common stock warrants		2,156,863
Warrants exercisable price per share (in dollars per share)		$ 3.56
Class of warrant or right, term	1 year 1 day
Series C Warrants
Class of Warrant or Right [Line Items]
Common stock warrants		2,156,863
Warrants exercisable price per share (in dollars per share)		$ 3.56
Class of warrant or right, term	18 months
Series D Warrants
Class of Warrant or Right [Line Items]
Common stock warrants		2,156,863
Warrants exercisable price per share (in dollars per share)		$ 3.56
Class of warrant or right, term	8 months

Stockholders' equity (deficit44

Stockholders' equity (deficit) - Shares Reserved for Issuance (Details) - shares	Dec. 31, 2015	Nov. 06, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity [Abstract]
Common stock, shares outstanding	12,946,018		8,862,114
Shares reserved for future issuance
Stock options outstanding	1,542,732		1,272,581	563,453
Shares available for grant under stock option plans	49,401
Restricted stock units	891,617
Common stock warrants	10,039,682	8,088,236
Total shares reserved for future issuance	12,523,432

Stockholders' equity (deficit45

Stockholders' equity (deficit) - Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions	May. 15, 2014	Dec. 31, 2015	Dec. 31, 2014	Mar. 24, 2015	Feb. 14, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans		49,401
Number of Shares:
Outstanding at the beginning of the period (in shares)		1,272,581	563,453
Granted (in shares)		467,183	712,204
Exercised (in shares)		0	0
Forfeited (in shares)		(192,167)	(3,076)
Expired (in shares)		(4,865)	0
Outstanding at the end of the period (in shares)		1,542,732	1,272,581
Exercisable at the end of the period (in shares)		817,002
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)		$ 4.19	$ 1.18
Granted (in dollars per share)		5.04	6.60
Exercised (in dollars per share)		0	0
Expired (in dollars per share)		15.20	0
Forfeited (in dollars per share)		5.23	11.90
Outstanding at the end of the period (in dollars per share)		4.28	4.19
Exercisable weighted average exercise price for exercisable options (in dollars per share)		$ 3.23
Outstanding, weighted average remaining contractual term (years)		7 years 6 months
Exercisable weighted average remaining contractual term (years)		5 years 3 months 18 days
Options, weighted average grant date fair value (in dollars per share)		$ 3.54	$ 5.40
Assumptions used to determine the fair value of the stock options
Volatility (as a percent)		99.69%	88.29%
Dividend yield		0.00%	0.00%
Expected life in years		6 years	6 years 6 months
Risk free interest rate (as a percent)		1.75%	1.98%
Options outstanding, intrinsic value		$ 0.4
Share price		$ 1.60			$ 12
Compensation cost not yet recognized, options		$ 4.6
Stock Option
Assumptions used to determine the fair value of the stock options
Compensation cost not yet recognized, period for recognition		1 year 5 months 1 day
2007 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares authorized under the plan	673,923
Number of shares authorized under the plan	1,283,226			2,483,226

Stockholders' equity (deficit46

Stockholders' equity (deficit) - Restricted Stock Units (Details) - $ / shares	1 Months Ended		12 Months Ended
	Nov. 30, 2015	Nov. 30, 2013	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at December 31 (in shares)			891,617
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at January 1 (in shares)			17,000
Number of award issued (in shares)			880,617
Units vested (in shares)			(6,000)
Units forfeited (in shares)			0
Unvested at December 31 (in shares)			891,617
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested at January 1 (in dollars per share)			$ 4.55
Units granted (in dollars per share)			2.31
Units vested (in dollars per share)			4.55
Unvested at December 31 (in dollars per share)			$ 2.34
Restricted stock units | CEO
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of award issued (in shares)		24,000	6,000
Restricted stock units | CEO | Vesting on October 21, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		25.00%
Restricted stock units | CEO | Vesting Equal Monthly Installments after Nov 1, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		75.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of award issued (in shares)			13,000
Restricted stock units | Executive Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	33 months

Stockholders' equity (deficit47

Stockholders' equity (deficit) - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 1,475	$ 951
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	335	130
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 1,140	$ 821

Retirement Savings Plan (Detail

Retirement Savings Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Defined contribution plan, employer matching contribution of employee's gross pay	3.00%
Defined contribution plan, cost recognized	$ 50,000	$ 48,000

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Care Capital, LLC
Related Party Transactions [Line Items]
Expense for services provided	$ 0	$ 70,000

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets:
Net operating loss carry forwards	$ 14,841	$ 11,044
Stock based compensation	749	357
Tax credits	1,720	1,516
Depreciation	(2)	1
Amortization	10,388	6,392
Accrued compensation	28	0
Accrued expenses	9	4
Accrued interest	0	12
Deferred tax assets	27,733	19,326
Less: valuation allowance	(27,733)	(19,326)
Net deferred tax asset	$ 0	$ 0

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Federal statutory rate	(34.00%)	(34.00%)
State income taxes	(2.80%)	0.73%
Valuation allowance	(36.80%)	33.27%
Effective tax rate	0.00%	0.00%

Income Taxes - Operating Loss C

Income Taxes - Operating Loss Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 41.9
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		$ 22.4

Income Taxes - Tax Credit Carry

Income Taxes - Tax Credit Carryforwards (Details) - Research Tax Credit Carryforward $ in Thousands	Dec. 31, 2015USD ($)
Federal
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 1,500
State
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 189

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 0	$ 0
Valuation allowance increase (decrease)	8,400,000	5,200,000
Unrecognized tax benefits	$ 0	$ 0

Commitments (Details)

Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,016	$ 118
2,017	122
2,018	125
2,019	129
2,020	55
Total future minimum payments due	549
Rent expense	$ 115	$ 62

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016USD ($)	Mar. 28, 2016USD ($)position	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Subsequent Event [Line Items]
Payments on term loan			$ 389	$ 0
Scenario, Forecast | Employee Severance and Related Benefits and Other Costs
Subsequent Event [Line Items]
Restructuring charges	$ 175
Subsequent Event | Initial Term Loan | Term Loan
Subsequent Event [Line Items]
Payments on term loan		$ 6,300
Subsequent Event | Employee Severance and Related Benefits and Other Costs
Subsequent Event [Line Items]
Restructuring and related cost, number of positions eliminated | position		5