Stock-based Compensation - Stock Option (Details) - Stock options - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Stock-based compensation expense
Shares available for future issuance	1,443,561
Shares
Outstanding at the beginning of the period (in shares)	784,011
Options granted (in shares)	207,700
Outstanding at the end of the period (in shares)	991,711
Exercisable at the end of the period (in shares)	373,148
Weighted average exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 10.70
Options granted (in dollars per share)	16.72
Outstanding at the end of the period (in dollars per share)	11.96
Exercisable at the end of the period (in dollars per share)	$ 11.20
Additional disclosures
Total cash received from stock option exercises	$ 0	$ 0
Weighted-average grant date fair value of options (in dollars per share)	$ 13.30
Maximum
Stock-based compensation expense
Expiration period	10 years