Stockholders' Equity and Redeemable Convertible Preferred Stock (Details 3) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	May. 24, 2015	Sep. 30, 2015
Number of Shares
Options expired	(176)
Employee
Number of Shares
Outstanding at beginning of year		5,243,877
Options granted		450,000
Options forfeited		(250,000)
Options expired		(176)
Outstanding at end of year		5,443,701
Options vested and expected to vest		5,443,701
Options vested and exercisable		5,406,076
Weighted Average Exercise Price
Outstanding at beginning of year		$ 4.97
Options granted		0.50
Options forfeited		0.00
Options expired		0.00
Outstanding at end of year		4.69
Options vested and expected to vest		4.69
Options vested and exercisable		$ 4.72
Total Intrinsic Value
Outstanding at beginning of year		$ 0
Outstanding at end of year		$ 34,500
Weighted Average Remaining Contractual Life (in years)
Weighted average remaining contractual life Outstanding, Beginning Balance		6 years
Options granted		4 years 8 months 12 days
Weighted average remaining contractual life Outstanding, Ending Balance		5 years 3 months 18 days
Options vested and expected to vest		5 years 3 months 18 days
Options vested and exercisable		5 years 3 months 18 days