Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows From Operating Activities
Net (loss)/income	$ (22,548)	$ 6,094	$ 15,494
Adjustments to reconcile net income/(loss) to net cash and cash equivalents provided by operating activities:
Stock-based compensation	12,936	9,217	6,782
Deferred taxes	(13,205)	(9,134)	(5,180)
Depreciation and amortization	44,638	44,612	33,742
Acquired in-process research and development ("IPR&D")	3,753	2,324	1,335
Non-cash interest	1,876	7,024	8,465
Loss on repurchase of Convertible notes	0	0	468
Asset impairment charge	445	75	0
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable, net	(23,664)	(7,287)	(4,743)
Inventories, net	(2,759)	(7,660)	(379)
Prepaid expenses and other current assets	(1,866)	403	(1,142)
Accounts payable	(2,294)	5,039	3,466
Accrued royalties	1,323	(3,372)	(3,708)
Current income taxes, net	4,982	(6,098)	6,184
Accrued government rebates	(1,075)	(73)	1,044
Returned goods reserve	10,369	4,043	4,278
Accrued expenses, accrued compensation, and other	2,356	424	968
Net Cash and Cash Equivalents Provided by Operating Activities	15,267	45,631	67,074
Cash Flows From Investing Activities
Acquisition of WellSpring Pharma Services Inc., net of cash acquired	0	0	(16,467)
Acquisition of product rights, IPR&D, and other related assets	(62,187)	(20,914)	(5,169)
Acquisition of property and equipment, net	(6,135)	(6,635)	(5,743)
Net Cash and Cash Equivalents Used in Investing Activities	(68,322)	(27,549)	(27,379)
Cash Flows From Financing Activities
Payment of debt issuance and convertible debt repurchase costs	0	0	(1,572)
Payments on Term Loan and Delayed Draw Term Loan agreements	(8,034)	(2,707)	(2,813)
Borrowings under Revolver agreement	15,000	0	0
Payments on Revolver agreement	(7,500)	0	0
Borrowings under Delayed Draw Term Loan agreement	0	118,000	0
Proceeds from stock option exercises and ESPP purchases	618	5,738	2,978
Repayment of Convertible Notes	0	(118,750)	(26,125)
Unwinding of portion of call option overlay, net	0	0	375
Treasury stock purchases for restricted stock vests	(1,523)	(1,031)	(659)
Net Cash and Cash Equivalents (Used in)/Provided by Financing Activities	(1,439)	1,250	(27,816)
Net Change in Cash and Cash Equivalents	(54,494)	19,332	11,879
Cash and cash equivalents, beginning of period	67,361	48,029	36,150
Cash and cash equivalents, end of period	12,867	67,361	48,029
Reconciliation of cash, cash equivalents, and restricted cash, beginning of period
Cash and cash equivalents	62,332	43,008	31,144
Restricted cash	5,029	5,021	5,006
Cash and cash equivalents, beginning of period	67,361	48,029	36,150
Reconciliation of cash, cash equivalents, and restricted cash, end of period
Cash and cash equivalents	7,864	62,332	43,008
Restricted cash	5,003	5,029	5,021
Cash and cash equivalents, end of period	12,867	67,361	48,029
Supplemental disclosure for cash flow information:
Cash paid for interest, net of amounts capitalized	6,931	6,092	6,285
Cash paid for income taxes	4,984	10,033	6,397
Supplemental non-cash investing and financing activities:
Acquisition of product rights, IPR&D, and other related assets included in returned goods reserve and derivatives and other non-current liabilities	391	500	0
Property and equipment purchased and included in accounts payable	$ 172	$ 723	$ 521