Fair Value Measurements (Details 1) - Recurring [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Common Stock Warrant Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		$ 63
Issuance of common stock warrant			53
Issuance of convertible notes
Change in fair value		6	10	[1]
End balance		69	63
2014/2015 Convertible Promissory Notes [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance			447
Issuance of convertible notes			1,818
Change in fair value	[1]		728
Extinguishment of convertible notes for Series B convertible preferred stock			(2,993)
End balance

[1] The change in the fair value of the common stock warrant and convertible notes payable was recorded as an increase to other income (expense) and interest expense of $677 and $63, respectively, in the statements of operations and comprehensive loss.