Warrants (Details) - USD ($)		1 Months Ended	12 Months Ended
	Dec. 12, 2016	Nov. 30, 2015	Dec. 31, 2019	Dec. 31, 2018	Aug. 13, 2019	Dec. 31, 2017
Warrants to Purchase Common Stock
Total fair value of warrants						$ 11,868,000
Number of unvested warrants cancelled					109,601
Share-based Compensation			$ 2,010,000	$ 1,658,000
Change in fair value of warrants				(1,632,000)
Reclassification into equity upon initial public offering				10,236,000
Performance Award
Warrants to Purchase Common Stock
Minimum gross proceeds for meeting performance requirement		$ 25,000,000
Warrants potentially issued for meeting performance requirement		234,860
Number of warrants issued	234,860
Warrants exercise price	$ 14.50
Total fair value of warrants	$ 661,000
Vesting period	5 years
Share-based Compensation			$ 82,000	132,000
Change in fair value of warrants				$ 1,600,000