Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 2,780	$ 3,979
New shares of common stock issued as a result of vesting RSUs (in shares)			164,146
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,064	$ 1,423	$ 2,780	$ 3,979
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	1,377,500	0	1,733,500	429,000
Options granted, weighted average grant date fair value (in dollars per share)	$ 3.01		$ 2.93	$ 3.25
Dividend yield			0.00%	0.00%
Expected stock price volatility			85.00%	80.00%
Risk-free interest rate			1.93%	1.84%
Expected option term			6 years	6 years
Unrecognized stock-based compensation expense expected to be recognized related to non-vested stock options	$ 7,180		$ 7,180
Weighted average amortization period			3 years 4 months 2 days
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs granted (in shares)	0	0	220,664	219,331
Weighted average grant date fair value of RSU's granted (in dollars per share)			$ 3.83	$ 4.75
Unrecognized stock-based compensation expense expected to be recognized related to non-vested RSUs	$ 2,241		$ 2,241
Weighted average amortization period			2 years 8 months 5 days
2013 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized for issuance (in shares)			2,500,000
Shares authorized for issuance (in shares)	16,624,469		16,624,469
Shares available for grant (in shares)	2,244,631		2,244,631