Stock-Based Compensation - Stock Option Activity (Details) - Stock options - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Number of Options Outstanding
Outstanding, beginning (in shares)	1,510,832	1,430,559
Options granted (in shares)	295,001	182,500
Options exercised (in shares)	67,000	32,227
Options forfeited (in shares)	131,486	70,000
Outstanding, ending (in shares)	1,607,347	1,510,832
Outstanding, Exercisable (in shares)	1,229,704	1,198,204
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 1.63	$ 1.84
Options granted (in dollars per share)	1.12	1.47
Options exercised (in dollars per share)	0.76	2.09
Options forfeited (in dollars per share)	0.97	2.61
Ending balance (in dollars per share)	0.83	1.63
Exercisable (in dollars per share)	$ 0.77	$ 1.63
Average Remaining Contractual Life (in years)	7 years 25 days
Average Remaining Contractual Life, Exercisable (in years)	6 years 5 months 23 days	6 years 8 months 23 days
Aggregate Intrinsic Value, Outstanding	$ 0
Aggregate Intrinsic Value, Exercisable	$ 0	$ 0