CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating Activities
Net loss	$ (53,400)	$ (31,458)
Adjustments for non-cash items:
Depreciation and amortization	52,691	55,336
Accretion of debt discount and debt issuance costs	9,411	8,624
Loss on prepayment of Senior Notes	5,364	5,777
Provision for inventory obsolescence	2,110	403
Gain on disposal of property and equipment	(275)
Stock-based compensation	6,959	8,238
Change in fair value of contingent consideration	(6,176)	527
Deferred income taxes		(12,232)
Other	264	472
Changes in assets and liabilities:
Accounts receivable	23,719	(8,354)
Receivables from collaborative partners	162	67
Inventories	490	(346)
Prepaid and other assets	173	(4,912)
Accounts payable and other accrued liabilities	(9,135)	(3,060)
Accrued rebates, returns and discounts	8,470	(3,251)
Interest payable	(2,716)	(2,889)
Net cash provided by operating activities	38,111	12,942
Investing Activities
Purchases of property and equipment	(504)	(2,538)
Proceeds from disposal of property and equipment	280
Purchases of marketable securities	(2,391)	(26,570)
Maturities of marketable securities	58,281	103,707
Net cash provided by investing activities	55,666	74,599
Financing Activities
Payment of contingent consideration liability	(1,293)	(600)
Repayment of Senior Notes	(100,000)	(100,000)
Prepayment fees for repayment of Senior Notes	(4,000)	(5,000)
Proceeds from issuance of common stock	7,242	5,163
Net cash used in financing activities	(98,261)	(100,804)
Shares withheld for payment of employee's withholding tax liability	(210)	(367)
Net increase in cash and cash equivalents	(4,484)	(13,263)
Cash and cash equivalents at beginning of year	117,709	101,084
Cash and cash equivalents at end of period	113,225	87,821
Supplemental Disclosure of Cash Flow Information
Net cash paid for income taxes	121	78
Cash paid for interest	30,187	35,823
Capitalized expenditures incurred but not yet paid	130	124
Convertible Notes
Adjustments for non-cash items:
Accretion of debt discount and debt issuance costs	8,213	7,542
Senior Notes
Adjustments for non-cash items:
Accretion of debt discount and debt issuance costs	$ 1,197	$ 1,082