CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 131,228	$ 91,426
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	72,018	77,455
Deferred income taxes	0	(27,973)
Share-based compensation	82,417	49,046
Gain on short-term investments, net	(10,526)	(3,135)
Gain on investments in privately-held companies	(9,569)	0
Impairment charges	3,045	2,806
Changes in assets and liabilities:
Accounts receivable	(51,936)	11,441
Inventories	15,558	(41,837)
Prepaid expenses and other assets	10,534	(128)
Accounts payable	10,850	13,661
Accrued and other liabilities	23,404	(4,273)
Net cash provided by operating activities	277,023	168,489
Cash flows from investing activities:
Purchase of short-term investments	(619,256)	(228,229)
Proceeds from sales and maturities of short-term investments	325,787	156,744
Proceeds from sales of property and equipment	48	3,239
Purchase of property and equipment	(26,951)	(28,992)
Purchase of intangibles and other assets	(4,298)	(7,428)
Proceeds from sale of an investment in a privately-held company	16,887	0
Purchase of investments in privately-held companies	(4,319)	(7,500)
Acquisition, net of cash acquired	0	(7,379)
Net cash used in investing activities	(312,102)	(119,545)
Cash flows from financing activities:
Principal payments on term debt	0	(74,000)
Payments on intangible asset financings	(8,590)	(6,519)
Proceeds from share issuances through employee stock plans	31,657	33,267
Net cash provided by (used in) financing activities	23,067	(47,252)
Net increase (decrease) in cash, cash equivalents, and restricted cash	(12,012)	1,692
Cash, cash equivalents, and restricted cash at beginning of period	64,650	70,498
Cash, cash equivalents, and restricted cash at end of period	$ 52,638	$ 72,190