Condensed Consolidated Balance Sheets (Parenthetical) (unaudited) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Accounts receivable, chargebacks and other deductions (in dollars)	$ 19,909	$ 13,101
Allowance for doubtful accounts (in dollars)	$ 133	$ 9
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	79,142,305	68,668,986
Common Stock, shares outstanding	77,469,385	66,996,066
Treasury stock, shares	1,672,920	1,672,920