Schedule II - Valuation and Qualifying Accounts and Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Charged to other accounts	$ 0	$ 0	$ 0
Valuation Allowance for Deferred Tax Assets
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	75,458	71,515	109,030
Charged to income	1,235	3,943	(37,515)
Charged to other accounts	0	0	0
Deductions	0	0	0
Balance at end of the period	76,693	75,458	71,515
Allowance for Rebates
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	12,261	5,648	3,842
Charged to income	81,217	37,070	17,236
Charged to other accounts	1,664	813	(132)
Deductions	(65,801)	(31,270)	(15,298)
Balance at end of the period	29,341	12,261	5,648
Allowance for Price Adjustments and Chargebacks
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	4,018	3,925	602
Charged to income	29,552	13,033	6,738
Charged to other accounts	1	0	(3)
Deductions	(26,647)	(12,940)	(3,412)
Balance at end of the period	6,924	4,018	3,925
Allowance for inventory obsolescence
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	187	243	0
Charged to income	149	(56)	243
Deductions	(92)	0	0
Balance at end of the period	$ 244	$ 187	$ 243