Implemented Accounting Pronouncements - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Bad debt expense	$ 400,000	$ 300,000	$ 1,227,000	$ 655,000
Allowance for doubtful accounts	2,200,000		2,200,000		$ 1,883,000
Net investment in sales-type leases	$ 1,900,000		1,900,000		$ 2,900,000
Credit loss expense			$ 0
Minimum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Sales-type leases terms	12 months		12 months
Maximum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Sales-type leases terms	36 months		36 months