Summary of Significant Accounting Policies - Summary of Product Revenue by Geographical Locations of Customers (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Total product revenue									$ 93,774	$ 76,051	$ 51,326
Product
Disaggregation Of Revenue [Line Items]
Total product revenue	$ 20,917	$ 18,019	$ 18,209	$ 17,504	$ 16,525	$ 15,399	$ 15,420	$ 13,564	74,649	60,908	43,568
Product | Europe, Middle East and Africa
Disaggregation Of Revenue [Line Items]
Total product revenue									52,499	46,974	36,241
Product | North America
Disaggregation Of Revenue [Line Items]
Total product revenue									20,936	12,696	6,325
Product | Other
Disaggregation Of Revenue [Line Items]
Total product revenue									$ 1,214	$ 1,238	$ 1,002