Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ (26,685)	$ 7,157
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	5,811	5,487
Loss on disposal and abandonment of intangible assets	113	18
Loss on disposal and impairment of property and equipment, net	1,305	1,563
Stock-based compensation	54,030	16,532
Deferred income taxes	(6,152)	(1,311)
Unrecognized tax benefits	612	613
Other noncash, net	2,596	1,822
Provision for expected credit losses	658	0
Change in assets and liabilities:
Accounts and notes receivable and contract assets	(9,375)	(11,006)
Inventory	(43,271)	(7,515)
Prepaid expenses and other assets	(8,551)	(5,761)
Accounts payable, accrued and other liabilities	16,708	(16,752)
Deferred revenue	5,224	6,577
Net cash used in operating activities	(6,977)	(2,576)
Cash flows from investing activities:
Purchases of investments	(292,597)	(141,992)
Proceeds from call / maturity of investments	158,670	25,319
Purchases of property and equipment	(7,551)	(7,861)
Proceeds from disposal of property and equipment	78	0
Purchases of intangible assets	(111)	(344)
Investment in unconsolidated affiliate	(4,700)	0
Net cash used in investing activities	(146,211)	(124,878)
Cash flows from financing activities:
Net proceeds from equity offering	306,779	0
Proceeds from options exercised	295	104
Income and payroll tax payments for net-settled stock awards	(5,767)	(2,132)
Net cash provided by (used in) financing activities	301,307	(2,028)
Effect of exchange rate changes on cash and cash equivalents	(1,115)	(252)
Net increase (decrease) in cash and cash equivalents	147,004	(129,734)
Cash and cash equivalents and restricted cash, beginning of period	172,355	351,027
Cash and cash equivalents and restricted cash, end of period	319,359	221,293
Supplemental disclosures:
Cash and cash equivalents	319,253	219,720
Restricted cash (Note 1)	106	1,573
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	319,359	221,293
Cash paid for income taxes, net of refunds	6,327	1,331
Non-cash transactions
Property and equipment purchases in accounts payable and accrued liabilities	$ 430	$ 91