CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Stock [Member] \| Stock Purchase Agreement
Issuance costs	$ 100
Common Stock [Member] \| At The Market
Issuance costs	107
IPO \| Common Stock [Member]
Issuance costs			$ 7,600
Follow-On Offering [Member] \| Common Stock [Member]
Issuance costs	$ 3,300
Private Placement \| Common Stock [Member]
Issuance costs		$ 2,400
Series B convertible preferred stock
Issuance costs			$ 206