Revenue - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2016	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2014
Revenues [Line Items]
Long-term trade receivables		$ 100,000		$ 100,000		$ 200,000
Long-term trade credit maintenance services term				1 year
Allowance for doubtful accounts		0		$ 0		$ 0
Deferred revenue, recognized		2,000,000.0	$ 1,000,000.0	7,400,000	$ 10,200,000
Company recognized revenue from performance obligations satisfied in a prior period		$ 0	$ 0.0	$ 0	$ 900,000
Minimum
Revenues [Line Items]
Expected long-term trade receivables collection period				2 years
Maximum
Revenues [Line Items]
Expected long-term trade receivables collection period				3 years
Itochu Corporation Agreement | Distribution Rights
Revenues [Line Items]
Distribution revenue reclassified as deferred revenue							$ 4,000,000.0
Remaining term of distribution agreement	8 years 6 months