Revenue Recognition - Activity of Product Revenue Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Product revenue reserves, beginning balance	$ 699	$ 0
Provision related to sales made in current period	18,268	3,533
Provision related to sales made in prior period	2,373	0
Payments and customer credits issued	(10,219)	(2,834)
Product revenue reserves, ending balance	11,121	699
Returns
Disaggregation of Revenue [Line Items]
Product revenue reserves, beginning balance	299	0
Provision related to sales made in current period	10,254	2,611
Provision related to sales made in prior period	2,373	0
Payments and customer credits issued	(5,366)	(2,312)
Product revenue reserves, ending balance	7,561	299
Chargebacks
Disaggregation of Revenue [Line Items]
Product revenue reserves, beginning balance	176	0
Provision related to sales made in current period	4,026	289
Provision related to sales made in prior period	0	0
Payments and customer credits issued	(3,303)	(113)
Product revenue reserves, ending balance	899	176
Others
Disaggregation of Revenue [Line Items]
Product revenue reserves, beginning balance	224	0
Provision related to sales made in current period	3,988	633
Provision related to sales made in prior period	0	0
Payments and customer credits issued	(1,550)	(409)
Product revenue reserves, ending balance	$ 2,661	$ 224