Stockholders' Equity - Schedule of 2017 Plan Options Outstanding (Details) - 2017 Plan - USD ($)		1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 01, 2019	Jan. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Number of Shares/Number of Options Outstanding
Outstanding at beginning of period (in shares)	343,550	343,550	343,550
Granted (in shares)			89,700
Forfeited (in shares)			(1,836)
Outstanding at end of period (in shares)			431,414	343,550
Weighted- average Exercise Price
Outstanding (in dollars per share)			$ 25.86	$ 28.97
Exercised (in dollars per share)			13.76
Forfeited (in dollars per share)			$ 16.64
Weighted- average Remaining Contractual Term (years)
Outstanding			8 years 11 months 1 day	8 years 11 months 12 days
Aggregate Intrinsic Value (in Thousands)
Outstanding			$ 0	$ 840
Options to purchase common stock
Number of Shares/Number of Options Outstanding
Options available (in shares)	157,881	157,881	157,881
Annual additional options authorized (in shares)	153,814		153,814
Granted (in shares)		89,700
Options available (in shares)			223,831	157,881