Stock Based Compensation - Summary of Activity under Incentive Plan (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Outstanding, Number of Shares, Beginning Balance | shares	857,311
Number of Shares, Options Granted | shares	91,800
Number of Shares, Options Exercised | shares	(16,250)
Number of Shares, Options Cancelled or forfeited | shares	(42,538)
Outstanding, Number of Shares, Ending Balance | shares	890,323
Outstanding, Weighted Average Exercise Price Per Share, Beginning Balance | $ / shares	$ 9.49
Weighted Average Exercise Price Per Share, Options Granted | $ / shares	6.10
Weighted Average Exercise Price Per Share, Options Exercised | $ / shares	3.80
Weighted Average Exercise Price Per Share, Options Cancelled or forfeited | $ / shares	10.97
Outstanding, Weighted Average Exercise Price Per Share, Ending Balance | $ / shares	$ 9.17
Aggregate Intrinsic Value, Ending Balance | $	$ 225