Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Cash Flows From Operating Activities
Net income	$ 5,037	$ 4,720	$ 10,064	$ 8,553
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Stock-based compensation			4,954	4,668
Deferred taxes			(2,581)	(4,602)
Depreciation and amortization	8,548	7,099	25,056	20,906
Acquired in-process research and development ("IPR&D")			1,335	0
Non-cash interest relating to convertible notes and loan cost amortization			6,392	5,723
Changes in operating assets and liabilities:
Accounts receivable, net			(7,548)	(16,279)
Inventories, net			118	4,605
Prepaid expenses and other current assets			(1,769)	(1,365)
Accounts payable			2,250	2,078
Accrued royalties			(4,709)	(840)
Accrued compensation and related expenses			(194)	378
Current income taxes, net			1,480	(4,450)
Accrued government rebates			1,084	(136)
Returned goods reserve			2,566	2,561
Accrued expenses and other			1,344	1,814
Net Cash and Cash Equivalents Provided by Operating Activities			39,842	23,614
Cash Flows From Investing Activities
Acquisition of WellSpring Pharma Services Inc., net of cash acquired			(17,067)	0
Acquisition of product rights, IPR&D, and other related assets			(5,169)	(50,956)
Acquisition of property and equipment, net			(4,736)	(6,922)
Net Cash and Cash Equivalents Used in Investing Activities			(26,972)	(57,878)
Cash Flows From Financing Activities
Payment of debt issuance costs			(153)	0
Payments on term loan agreement			(1,875)	0
Net borrowings under line of credit agreement			0	25,000
Proceeds from stock option exercises			2,817	191
Treasury stock purchases for restricted stock vestings			(659)	(259)
Net Cash and Cash Equivalents Provided by Financing Activities			130	24,932
Change in Cash, Cash Equivalents, and Restricted Cash			13,000	(9,332)
Cash, cash equivalents, and restricted cash, beginning of period			36,150	32,367	$ 32,367
Cash, cash equivalents, and restricted cash, end of period	49,150	23,035	49,150	23,035	36,150
Reconciliation of cash, cash equivalents, and restricted cash, beginning of period
Cash and cash equivalents			31,144	27,365	27,365
Restricted cash			5,006	5,002	5,002
Cash, cash equivalents, and restricted cash, beginning of period			36,150	32,367	32,367
Reconciliation of cash, cash equivalents, and restricted cash, end of period
Cash and cash equivalents	44,136	18,031	44,136	18,031	31,144
Restricted cash	5,014	5,004	5,014	5,004	5,006
Cash, cash equivalents, and restricted cash, end of period	$ 49,150	$ 23,035	49,150	23,035	$ 36,150
Supplemental disclosure for cash flow information:
Cash paid for interest, net of amounts capitalized			3,763	2,197
Cash paid for income taxes			3,890	12,493
Supplemental non-cash investing and financing activities:
Property and equipment purchased and included in accounts payable			$ 110	$ 354