Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Stock-Based Compensation
Options Available for Grant, Outstanding, Beginning balance	342,500
Options Available for Grant, Outstanding, Ending balance	273,548	342,500
Number of Options, Outstanding, Beginning balance	1,414,730
Number of Options, Options granted	74,000
Number of Options, Options exercised	(2,050)
Number of Options, Options cancelled/forfeited	(5,048)
Number of Options, Outstanding, Ending balance	1,481,632	1,414,730
Number of Options, exercisable	773,583
Number of Options, vested and expected to vest	1,481,634
Weighted - Average Exercise Price Per Share, Options outstanding, Beginning balance	$ 5.28
Weighted - Average Exercise Price Per Share, Options granted	7.88
Weighted - Average Exercise Price Per Share, Options exercised	4.42
Weighted - Average Exercise Price Per Share, Options cancelled/forfeited	4.97
Weighted - Average Exercise Price Per Share, Options outstanding, Ending balance	5.41	$ 5.28
Weighted - Average Exercise Price Per Share, Options exercisable	4.55
Weighted - Average Exercise Price Per Share, Options vested and expected to vest	$ 5.41
Weighted - Average Remaining Contractual Life, Options outstanding	7 years 6 months	7 years 7 months 6 days
Weighted - Average Remaining Contractual Life, Options exercisable	6 years
Weighted - Average Remaining Contractual Life, Options vested and expected to vest	7 years 6 months
Aggregate Intrinsic Value, Options outstanding	$ 4,406	$ 4,267
Aggregate Intrinsic Value, Options exercised	8
Aggregate Intrinsic Value, Options exercisable	2,963
Aggregate Intrinsic Value, Options vested and expected to vest	$ 4,406