Product Revenue Reserves and Allowances (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2017
Product Revenue Allowance and Reserves
Summary of Activity of Product Revenue Allowance and Reserves
Beginning balance			$ 3,638	$ 3,638	$ 0
Provision related to sales in the current year	$ 10,600	$ 8,600	6,100	25,329	1,443
Adjustments related to prior period sales	77	(29)	245	(293)	0
Credits and payments made	8,838	$ 6,745	2,981	(18,464)	0
Ending balance	10,210			10,210	1,443
Chargebacks, Discounts, and Fees
Summary of Activity of Product Revenue Allowance and Reserves
Beginning balance			1,986	1,986	0
Provision related to sales in the current year				9,750	688
Adjustments related to prior period sales				(76)
Credits and payments made				(8,971)
Ending balance	2,689			2,689	688
Government and other rebates
Summary of Activity of Product Revenue Allowance and Reserves
Beginning balance			1,231	1,231	0
Provision related to sales in the current year				15,350	459
Adjustments related to prior period sales				(106)
Credits and payments made				(9,257)
Ending balance	7,218			7,218	459
Returns
Summary of Activity of Product Revenue Allowance and Reserves
Beginning balance			$ 421	421	0
Provision related to sales in the current year				229	296
Adjustments related to prior period sales				(111)
Credits and payments made				(236)
Ending balance	$ 303			$ 303	$ 296