Schedule II - Valuation and Qualifying Accounts and Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation Allowance for Deferred Tax Assets
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	$ 76,079	$ 75,458	$ 71,515
Charged to income	(9,584)	621	3,943
Charged to other accounts	0	0	0
Deductions	0	0	0
Balance at end of the period	66,495	76,079	75,458
Allowance for Rebates
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	29,429	12,261	5,648
Charged to income	113,854	80,404	37,070
Charged to other accounts		2,565	813
Deductions	(109,036)	(65,801)	(31,270)
Balance at end of the period	34,247	29,429	12,261
Allowance for Distribution Fees and Chargebacks
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	6,005	4,018	3,925
Charged to income	27,581	29,552	13,033
Charged to other accounts		(901)	0
Deductions	(28,084)	(26,664)	(12,940)
Balance at end of the period	5,502	6,005	4,018
Allowance for inventory obsolescence
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the period	384	187	243
Charged to income	1,870	289	(56)
Charged to other accounts	0	0	0
Deductions	0	(92)	0
Balance at end of the period	$ 2,254	$ 384	$ 187