Condensed Consolidated Balance Sheets (Parenthetical) (unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Accounts receivable, chargebacks and other deductions (in dollars)	$ 13,154	$ 3,711
Allowance for doubtful accounts (in dollars)	$ 27	$ 84
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	68,561,678	59,894,362
Common Stock, shares outstanding	66,888,758	58,221,442
Treasury stock, shares	1,672,920	1,672,920