Schedule II -Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 1,646
Balance at End of Period	1,821	$ 1,646
Reserve for Uncollectible Accounts Receivable and Sales Return [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	1,646	1,568	$ 873
Charged to Costs and Expenses	440	464	724
Deductions	(286)	(343)	(116)
Other	21	(43)	87
Balance at End of Period	1,821	1,646	1,568
Deferred Tax Valuation Allowance [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	6,112	5,309	4,116
Charged to Costs and Expenses	1,200	803	1,193
Deductions	0	0	0
Other	0	0	0
Balance at End of Period	$ 7,312	$ 6,112	$ 5,309