Accrued Liabilities (Narrative) (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Discount and Distribution Fees	$ 1,575	$ 3,094
Government rebates and chargebacks	2,358	8,901
Assistance and Other Discounts	1,133	3,457
Product return	3,182	4,681
Accrued liabilities, amounts received in advance of revenue recognition	8,248	$ 20,133
Allowances for current period sales	13,437
Allowances for prior period sales	1,961
Payments for current period sales	(9,106)
Payments for prior period sales	(18,177)
Discount and Distribution Fees [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	3,069
Allowances for prior period sales	0
Payments for current period sales	(1,544)
Payments for prior period sales	(3,044)
Government Rebates and Chargebacks [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	6,455
Allowances for prior period sales	1,841
Payments for current period sales	(4,929)
Payments for prior period sales	(9,910)
Assistance and Other Discounts [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	2,962
Allowances for prior period sales	120
Payments for current period sales	(2,401)
Payments for prior period sales	(3,005)
Product Returns [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances for current period sales	951
Allowances for prior period sales	0
Payments for current period sales	(232)
Payments for prior period sales	$ (2,218)