CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 87,049	$ 54,369
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	47,449	52,674
Deferred income taxes	0	(28,085)
Share-based compensation	51,191	29,890
Gain on short-term investments, net	(6,558)	(1,828)
Gain on investments in privately-held companies	(9,569)	0
Impairment charges	2,843	1,567
Changes in assets and liabilities:
Accounts receivable	(49,726)	(1,451)
Inventories	11,800	(30,598)
Prepaid expenses and other assets	4,047	718
Accounts payable	1,969	12,530
Accrued and other liabilities	6,509	12,334
Net cash provided by operating activities	147,004	102,120
Cash flows from investing activities:
Purchase of short-term investments	(364,777)	(82,486)
Proceeds from sales and maturities of short-term investments	198,221	76,289
Proceeds from sales of property and equipment	0	3,239
Purchase of property and equipment	(15,208)	(20,078)
Purchase of intangibles and other assets	(2,850)	(6,995)
Proceeds from sale of an investment in a privately-held company	16,887	0
Purchase of investments in privately-held companies	(4,247)	(6,000)
Acquisition, net of cash acquired	0	(7,129)
Net cash used in investing activities	(171,974)	(43,160)
Cash flows from financing activities:
Principal payments on term debt	0	(74,000)
Payments on intangible asset financings	(4,019)	(3,446)
Proceeds from share issuances through employee stock plans	18,121	19,341
Net cash provided by (used in) financing activities	14,102	(58,105)
Net increase (decrease) in cash, cash equivalents, and restricted cash	(10,868)	855
Cash, cash equivalents, and restricted cash at beginning of period	64,650	70,498
Cash, cash equivalents, and restricted cash at end of period	$ 53,782	$ 71,353