Condensed Consolidated Balance Sheets (Parenthetical) $ in Thousands	Mar. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares
Statement Of Financial Position [Abstract]
Accounts receivable, related party amount, current | $	$ 331	$ 88
Prepaid expenses and other current assets, related party amount | $	4,775	3,417
Accrued expenses related party amount, current | $	2,483	1,700
Deferred revenue non-current related party amount | $	$ 57,755	$ 57,780
Common stock, shares authorized	53,325,963	52,183,139
Common stock, shares issued	52,943,581	52,160,798
Common stock, shares outstanding	52,635,645	51,852,862
Common stock, conditional capital	20,498,996	20,498,996
Treasury stock, shares	307,936	307,936