Stockholders' Equity - Schedule of 2017 Plan Options Outstanding (Details) - 2017 Plan - USD ($) $ / shares in Units, $ in Thousands				5 Months Ended	9 Months Ended
	Feb. 13, 2018	Jan. 04, 2018	Jan. 01, 2018	Dec. 31, 2017	Sep. 30, 2018	Sep. 08, 2017	Jul. 31, 2017
Number of Shares/Number of Options Outstanding
Granted (in shares)				214,000	188,550
Forfeited (in shares)				(40,000)	(27,000)
Outstanding at beginning of period (in shares)			174,000	0	174,000
Outstanding at end of period (in shares)				174,000	335,550
Weighted- average Exercise Price
Exercised (in dollars per share)				$ 37.62	$ 23.49
Forfeited (in dollars per share)				49.93	24.84
Outstanding (in dollars per share)				$ 34.78	$ 29.24		$ 0
Weighted- average Remaining Contractual Term (years)
Granted				9 years 8 months 16 days
Outstanding				9 years 8 months 16 days	9 years 2 months 5 days
Aggregate Intrinsic Value (in Thousands)
Outstanding					$ 50
Options to purchase common stock
Number of Shares/Number of Options Outstanding
Options available (in shares)				226,000	165,881		0
Total options authorized (in shares)						400,000	400,000
Annual additional options authorized (in shares)			101,431		101,431
Granted (in shares)	100,000	57,050			31,500
Weighted- average Exercise Price
Exercised (in dollars per share)	$ 24.79	$ 24.84