Accrued Liabilities (Narrative) (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Discount and Distribution Fees	$ 2,247	$ 3,094
Government rebates and chargebacks	3,133	8,901
Assistance and Other Discounts	1,337	3,457
Product return	3,548	4,681
Accrued liabilities, amounts received in advance of revenue recognition	10,265	$ 20,133
Allowances for current period sales	19,653
Allowances for prior period sales	2,044
Payments for current period sales	(12,713)
Payments for prior period sales	(18,852)
Discount and Distribution Fees [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	4,122
Allowances for prior period sales	50
Payments for current period sales	(1,944)
Payments for prior period sales	(3,075)
Government Rebates and Chargebacks [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	10,020
Allowances for prior period sales	1,841
Payments for current period sales	(7,401)
Payments for prior period sales	(10,228)
Assistance and Other Discounts [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	4,194
Allowances for prior period sales	120
Payments for current period sales	(3,105)
Payments for prior period sales	(3,329)
Product Returns [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	1,317
Allowances for prior period sales	33
Payments for current period sales	(263)
Payments for prior period sales	$ (2,220)