Stock-Based Compensation - Stock Option Activity (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2014	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding beginning of period (in shares)	6,381,447
Options granted	196,600
Exercised (in shares)	0
Forfeited (in shares)	(497,352)
Outstanding end of period (in shares)	6,080,695
Vested and expected to vest (in shares)	6,070,694
Exercisable (in shares)	3,435,334
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding beginning of period (in dollars per share)	$ 1.90
Granted (in dollars per share)	1.14
Exercised (in dollars per share)	0.00
Forfeited (in dollars per share)	1.94
Outstanding end of period (in dollars per share)	1.87
Vested and expected to vest (in dollars per share)	1.88
Exercisable (in dollars per share)	$ 1.89
Outstanding, weighted average remaining contractual term	7 years 5 days	7 years 4 months 15 days
Vested and expected to vest, weighted average remaining contractual term	7 years 5 days
Exercisable, weighted average remaining contractual term	6 years 11 months 22 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, intrinsic value	$ 0		$ 20,033
Vested and expected to vest, intrinsic value	0
Exercisable, intrinsic value	$ 0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 8 months