Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Underwriting discounts and commissions and expenses		$ 1,345	$ 3,458
Issuance costs, equity component of convertible debt	$ 3,725