Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows From Operating Activities
Net (loss)/income	$ (1,076)	$ 3,934	$ 15,375
Adjustments to reconcile net (loss)/income to net cash and cash equivalents provided by operating activities:
Stock-based compensation	6,090	6,067	3,856
Deferred taxes	3,560	(8,911)	(1,877)
Depreciation and amortization	27,928	22,343	6,900
Non-cash interest relating to convertible notes and loan cost amortization	7,666	7,281	6,831
Intangible asset impairment charge	903	6,685	0
Changes in operating assets and liabilities:
Accounts receivable, net	(12,893)	(23,963)	(4,635)
Inventories, net	5,356	(1,938)	(5,869)
Prepaid expenses and other current assets	(17)	(647)	(314)
Accounts payable	3	1,076	(1,027)
Accrued royalties	(417)	6,269	(96)
Accrued compensation and related expenses	675	443	(160)
Current income taxes, net	(3,560)	3,525	(5,380)
Accrued government rebates	2,039	1,260	2,367
Returned goods reserve	2,518	3,108	1,203
Accrued expenses and other	644	940	90
Net Cash and Cash Equivalents Provided by Operating Activities	39,419	27,472	17,264
Cash Flows From Investing Activities
Acquisition of product rights and other related assets	(97,624)	(144,494)	(30,500)
Acquisition of property and equipment	(10,369)	(4,566)	(2,183)
Net Cash and Cash Equivalents Used in Investing Activities	(107,993)	(149,060)	(32,683)
Cash Flows From Financing Activities
Payment of debt issuance costs	(2,737)	(294)	0
Borrowings under term loan agreement	75,000	0	0
Proceeds from stock option exercises	353	1,570	819
Excess tax benefit from share-based compensation awards	0	617	360
Repurchase of common stock under the stock repurchase program	0	(2,500)	0
Treasury stock purchases for restricted stock vestings	(259)	(122)	(113)
Net Cash and Cash Equivalents Provided by/(Used in) Financing Activities	72,357	(729)	1,066
Net Change in Cash and Cash Equivalents	3,783	(122,317)	(14,353)
Cash, cash equivalents, and restricted cash, beginning of period	32,367	154,684	169,037
Cash, cash equivalents, and restricted cash, end of period	36,150	32,367	154,684
Reconciliation of cash, cash equivalents, and restricted cash, beginning of period
Cash and cash equivalents	27,365	154,684	169,037
Restricted cash	5,002	0	0
Cash, cash equivalents, and restricted cash, beginning of period	32,367	154,684	169,037
Reconciliation of cash, cash equivalents, and restricted cash, end of period
Cash and cash equivalents	31,144	27,365	154,684
Restricted cash	5,006	5,002	0
Cash, cash equivalents, and restricted cash, end of period	36,150	32,367	154,684
Supplemental disclosure for cash flow information:
Cash paid for interest, net of amounts capitalized	3,759	4,078	4,149
Cash paid for income taxes	17,786	9,537	13,255
Supplemental non-cash investing and financing activities:
Accrued royalties related to asset purchase	0	3,882	0
Property and equipment purchased and included in accounts payable	$ 485	$ 247	$ 439