Revenue - Summary of Revenue Disaggregated by Types and Geography (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	$ 10,086	$ 20,862	$ 38,560	$ 71,313
Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	6,210	18,696	28,295	65,475
Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	3,758	2,048	9,909	5,482
Distribution Rights
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	118	118	356	356
U.S.
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	2,786	7,247	13,584	31,488
U.S. | Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	618	6,107	7,920	28,394
U.S. | Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	2,168	1,140	5,664	3,094
Outside of U.S. ("OUS")
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	7,300	13,615	24,976	39,825
Outside of U.S. ("OUS") | Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	5,592	12,589	20,375	37,081
Outside of U.S. ("OUS") | Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	1,590	908	4,245	2,388
Outside of U.S. ("OUS") | Distribution Rights
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	$ 118	$ 118	$ 356	$ 356