Summary of Significant Accounting Policies - Summary of Balances and Activity in Each of Product Revenue Allowance and Reserve Categories (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	$ 348
Provision related to current period sales	2,726
Adjustment related to prior period sales	(32)
Credits or payments made during the period	(1,555)
Balance at September 30, 2019	1,487
Chargebacks, Discounts and Fees [Member]
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	50
Provision related to current period sales	824
Adjustment related to prior period sales	(4)
Credits or payments made during the period	(601)
Balance at September 30, 2019	269
Government and Other Rebates [Member]
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	293
Provision related to current period sales	1,648
Adjustment related to prior period sales	(28)
Credits or payments made during the period	(954)
Balance at September 30, 2019	959
Returns [Member]
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	5
Provision related to current period sales	254
Adjustment related to prior period sales	0
Credits or payments made during the period	0
Balance at September 30, 2019	$ 259