CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net income (loss)	$ (157,833)	$ 85,201
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Intangible asset amortization	62,847	56,885
Share-based compensation	28,654	27,552
Impairment charge	136,139	0
Depreciation	4,527	3,539
Acquired in-process research and development	202,250	56,000
Loss on disposal of assets	73	3
Deferred tax benefit	(63,976)	(17,053)
Provision for losses on accounts receivable and inventory	2,620	528
Amortization of debt discount and deferred financing costs	12,000	11,133
Other non-cash transactions	1,902	(738)
Changes in assets and liabilities:
Accounts receivable	37,861	(56,960)
Inventories	(10,235)	(8,688)
Prepaid expenses and other current assets	(17,843)	(988)
Other non-current assets	323	426
Operating lease assets	3,195	2,108
Accounts payable	19,604	1,554
Accrued liabilities	(12,198)	(3,730)
Income taxes payable	20,829	39,726
Deferred revenue	(1,180)	(1,874)
Other non-current liabilities	7,316	6,773
Operating lease liabilities, less current portion	(3,906)	856
Net cash provided by operating activities	272,969	202,253
Investing activities
Proceeds from maturity of investments	345,000	345,000
Purchases of property, plant and equipment	(4,830)	(7,948)
Acquired in-process research and development	(202,250)	(56,000)
Acquisition of intangible assets	(13,000)	0
Acquisition of investments	(185,000)	(115,000)
Net cash (used in) provided by investing activities	(60,080)	166,052
Financing activities
Proceeds from employee equity incentive and purchase plans	13,264	3,057
Payment of employee withholding taxes related to share-based awards	(13,547)	(13,810)
Repayments of long-term debt	(8,347)	(8,347)
Share repurchases	(139,053)	(111,249)
Net cash used in financing activities	(147,683)	(130,349)
Effect of exchange rates on cash and cash equivalents	(948)	(112)
Net increase in cash and cash equivalents	64,258	237,844
Cash and cash equivalents, at beginning of period	637,344	309,622
Cash and cash equivalents, at end of period	$ 701,602	$ 547,466