Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Operating expenses:
Research and development	$ 2,633,000us-gaap_ResearchAndDevelopmentExpense	$ 1,189,000us-gaap_ResearchAndDevelopmentExpense
General and administrative	1,987,000us-gaap_GeneralAndAdministrativeExpense	744,000us-gaap_GeneralAndAdministrativeExpense
Total operating expenses	4,620,000us-gaap_OperatingExpenses	1,933,000us-gaap_OperatingExpenses
Loss from operations	(4,620,000)us-gaap_OperatingIncomeLoss	(1,933,000)us-gaap_OperatingIncomeLoss
Other income (expense):
Investment income	40,000us-gaap_InvestmentIncomeNet
Interest expense		(828,000)us-gaap_InterestExpense
Other expense		(70,000)us-gaap_OtherNonoperatingIncomeExpense
Total other income (expense)	40,000us-gaap_NonoperatingIncomeExpense	(898,000)us-gaap_NonoperatingIncomeExpense
Net loss	(4,580,000)us-gaap_NetIncomeLoss	(2,831,000)us-gaap_NetIncomeLoss
Unrealized gain on available-for-sale investments	6,000
Accretion of redeemable convertible preferred stock to redemption value		(1,512,000)
Net loss attributable to common stockholders	(4,580,000)	(4,343,000)
Net loss per share attributable to common stockholders - basic and diluted (in Dollars per share)	$ (0.28)us-gaap_EarningsPerShareBasicAndDiluted	$ (18.09)us-gaap_EarningsPerShareBasicAndDiluted
Weighted-average common shares outstanding used in net loss per share attributable to common stockholders - basic and diluted (in Shares)	16,448,688	240,138
Included in operating expenses, above, are the following amounts for non-cash stock based compensation expense
Allocated Share Based Compensation Expense	407,000	17,000
Comprehensive loss	(4,574,000)	(2,831,000)
Research and Development Expense [Member]
Included in operating expenses, above, are the following amounts for non-cash stock based compensation expense
Allocated Share Based Compensation Expense	110,000	10,000
General and Administrative Expense [Member]
Included in operating expenses, above, are the following amounts for non-cash stock based compensation expense
Allocated Share Based Compensation Expense	$ 297,000	$ 7,000

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