CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities
Net loss	$ (69,392)	$ (44,352)
Adjustments for non-cash items:
Depreciation and amortization	79,031	83,019
Accretion of debt discount and debt issuance costs	14,249	13,084
Loss on prepayment of Senior Notes	5,364	5,777
Provision for inventory obsolescence	2,345	754
Gain on disposal of property and equipment	(275)
Stock-based compensation	9,922	12,602
Change in fair value of contingent consideration	(7,517)	918
Deferred income taxes		(17,826)
Other	244	617
Changes in assets and liabilities:
Accounts receivable	24,864	(15,833)
Receivables from collaborative partners	27	134
Inventories	272	(1,519)
Prepaid and other assets	(4,428)	(9,134)
Accounts payable and other accrued liabilities	(20,648)	3,276
Accrued rebates, returns and discounts	5,463	3,614
Interest payable	(4,616)	(4,903)
Net cash provided by operating activities	34,905	30,228
Investing Activities
Purchases of property and equipment	(563)	(2,786)
Proceeds from disposal of property and equipment	281
Purchases of marketable securities	(7,074)	(48,861)
Maturities of marketable securities	60,681	108,207
Sales of marketable securities		2,007
Net cash provided by investing activities	53,325	58,567
Financing Activities
Payment of contingent consideration liability	(1,673)	(940)
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	7,529	6,785
Net cash used in financing activities	(98,354)	(99,522)
Shares withheld for payment of employee's withholding tax liability	(210)	(367)
Net decrease in cash and cash equivalents	(10,124)	(10,727)
Cash and cash equivalents at beginning of year	117,709	101,084
Cash and cash equivalents at end of period	107,585	90,357
Supplemental Disclosure of Cash Flow Information
Net cash paid for income taxes	121	83
Cash paid for interest	44,832	53,043
Capitalized expenditures incurred but not yet paid	87	392
Convertible Notes
Adjustments for non-cash items:
Accretion of debt discount and debt issuance costs	12,438	11,421
Senior Notes
Adjustments for non-cash items:
Accretion of debt discount and debt issuance costs	$ 1,811	$ 1,663