CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities
Net income	$ 105,202	$ 449,375
Adjustments to reconcile net income to net cash provided by operating activities:
Intangible asset amortization	192,505	181,324
Share-based compensation	89,614	84,626
Impairment charge	136,139	0
Depreciation	14,076	10,885
Acquired in-process research and development	215,250	109,975
Deferred tax benefit	(120,909)	(167,935)
Provision for losses on accounts receivable and inventory	9,148	3,847
Loss on extinguishment of debt	5,089	0
Amortization of debt discount and deferred financing costs	40,613	34,415
Other non-cash transactions	12,672	(1,638)
Changes in assets and liabilities:
Accounts receivable	(5,004)	(4,307)
Inventories	(21,861)	(23,028)
Prepaid expenses and other current assets	(64,902)	(22,858)
Other non-current assets	13,941	(540)
Operating lease assets	9,730	10,919
Accounts payable	20,645	29,104
Accrued liabilities	26,510	(37,369)
Income taxes payable	15,089	42,813
Deferred revenue	(3,540)	(4,234)
Other non-current liabilities	33,254	(3,634)
Operating lease liabilities, less current portion	(9,884)	(3,137)
Net cash provided by operating activities	713,377	688,603
Investing activities
Proceeds from maturity of investments	920,000	820,000
Purchases of property, plant and equipment	(10,889)	(32,998)
Acquisitions, net of cash acquired	0	(55,074)
Acquired in-process research and development	(215,250)	(61,700)
Acquisition of intangible assets	(113,000)	(80,500)
Acquisition of investments	(1,661,750)	(585,975)
Net cash provided by (used in) investing activities	(1,080,889)	3,753
Financing activities
Net proceeds from issuance of Exchangeable Senior Notes, due 2026	981,381	0
Proceeds from revolving credit facility	500,000	0
Proceeds from employee equity incentive and purchase plans	34,339	26,090
Payment of employee withholding taxes related to share-based awards	(15,760)	(15,900)
Repayments of long-term debt	(25,040)	(25,040)
Share repurchases	(146,537)	(191,115)
Payments for partial repurchase of Exchangeable Senior Notes, due 2021	(356,188)	0
Repayments under revolving credit facility	(500,000)	0
Net cash provided by (used in) financing activities	472,195	(205,965)
Effect of exchange rates on cash and cash equivalents	(85)	(838)
Net increase in cash and cash equivalents	104,598	485,553
Cash and cash equivalents, at beginning of period	637,344	309,622
Cash and cash equivalents, at end of period	$ 741,942	$ 795,175