Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity/(Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015
Underwriting commissions and discounts	$ 3,000
Series B-1 Convertible Preferred Stock
Temporary equity issuance costs		$ 6