Warrants (Tables)

6 Months Ended

Jun. 30, 2015

Warrants.

Roll-forward of the fair value of warrants determined by Level 3 inputs

The following table provides a roll-forward of the fair value of the 2014 Warrants and 2015 Warrants determined by Level 3 inputs (in thousands):

	Fair Value
Balance at December 31, 2014	$	108
Issuance of warrants at fair value	107
Change in fair value, recorded as a component of other income, net	(9		)
Reclassification to additional paid-in capital	(206		)
Balance at June 30, 2015	$	—

Schedule of weighted-average assumptions

	June 30, 2015 (1)		December 31, 2014
Risk-free interest rate	1.97	%	1.95	%
Expected dividend yield	0.00	%	0.00	%
Expected term (in years)	6.5		6.7
Expected volatility	75.79	%	78.16	%

(1)Represents the date the warrants for series B convertible preferred stock converted to warrants for common stock