Summary of Significant Accounting Policies - Summary of Balances and Activity in Each of Product Revenue Allowance and Reserve Categories (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	$ 348
Provision related to current period sales	582
Adjustment related to prior period sales	(30)
Credit or payments made during the period	(104)
Balance at March 31, 2019	796
Chargebacks, Discounts and Fees [Member]
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	50
Provision related to current period sales	155
Credit or payments made during the period	(104)
Balance at March 31, 2019	101
Government and Other Rebates [Member]
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	293
Provision related to current period sales	375
Adjustment related to prior period sales	(30)
Balance at March 31, 2019	638
Returns [Member]
Revenue Allowance and Reserves Balance [Abstract]
Balance at December 31, 2018	5
Provision related to current period sales	52
Balance at March 31, 2019	$ 57