Revenue - Summary of Revenue Disaggregated by Types and Geography (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	$ 20,284	$ 26,190
Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	18,874	25,379
Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	1,291	692
Distribution Rights
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	119	119
U.S.
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	634	13,931
U.S. | Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	0	13,535
U.S. | Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	634	396
Outside of U.S. ("OUS")
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	19,650	12,259
Outside of U.S. ("OUS") | Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	18,874	11,844
Outside of U.S. ("OUS") | Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	657	296
Outside of U.S. ("OUS") | Distribution Rights
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	$ 119	$ 119