Stock-Based Compensation - Restricted Stock Units (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares
Weighted Average Exercise Price Per Share
Unrecognized compensation expense, weighted-average period expected to be recognized	2 years 8 months 12 days
2016 Employee Incentive Plan [Member] | RSU
Number of Restricted Stock Units
Balance, beginning of period | shares	30,680
Granted | shares	80,950
Vested | shares	(15,070)
Cancelled/forfeited | shares	(3,000)
Balance, end of period | shares	93,560
Weighted Average Exercise Price Per Share
Balance, beginning of period (price per share) | $ / shares	$ 10.55
Granted (price per share) | $ / shares	8.48
Vested (price per share) | $ / shares	13.41
Cancelled/forfeited (price per share) | $ / shares	8.10
Balance, end of period (price per share) | $ / shares	$ 8.38
Unrecognized stock-based compensation expense | $	$ 594,000
Unrecognized compensation expense, weighted-average period expected to be recognized	2 years 8 months 12 days