Accrued Expenses & Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued expenses and other current liabilities:
Accrued compensation and benefits	$ 11,169	$ 10,438
Accrued consulting and professional fees	3,810	3,927
Accrued research and development	8,734	7,503
Accrued revenue reserves	38,450	10,155
Accrued other	3,213	6,358
Total accrued expenses and other current liabilities	$ 65,376	$ 38,381