CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (31,543)	$ (80,887)
Adjustments to reconcile net loss to net cash provided by operating activities:
Stock-based compensation	19,613	21,657
Depreciation	20,853	16,226
Amortization of intangible assets	13,848	13,096
Non-cash interest expense and amortization of convertible debt issuance costs	5,394	5,104
Impairment of assets held for sale	0	15,137
Deferred income taxes	618	(2,118)
Loss on equity investment	521	424
(Gain) loss from disposal of property, plant, and equipment	(83)	141
Change in fair value of earn-out liability	(1,800)	0
Change in operating assets and liabilities, net of impact of acquisitions:
Accounts receivable	11,014	10,423
Unbilled receivables	126,324	113,264
Prepaid expenses and other assets	2,188	4,532
Inventories	(4,132)	(3,121)
Accounts payable	1,063	4,798
Accrued salaries and benefits and other liabilities	(5,067)	(2,179)
Income taxes payable	(13,317)	(10,824)
Deferred revenue	3,003	(5,618)
Operating lease liabilities	(5,105)	(6,931)
Net cash provided by operating activities	143,392	93,124
Cash flows from investing activities:
Purchases of property, plant, and equipment	(20,799)	(4,161)
Purchases of marketable securities	(655,063)	(463,850)
Maturities of marketable securities	527,971	377,852
Proceeds from sale of marketable securities	2,948	2,000
Settlement of working capital adjustment from disposal of business	(1,131)	0
Investment in privately-held company	0	(1,000)
Proceeds from sale of property, plant and equipment	0	29
Acquisition of business, net of cash acquired	0	(21,779)
Net cash used in investing activities	(146,074)	(110,909)
Cash flows from financing activities:
Proceeds received from issuance of common stock under employee stock plans	8,083	11,748
Payments of taxes on restricted stock units	(8,785)	(5,665)
Payments under installment payment arrangement	(9,152)	(4,330)
Net cash provided by (used in) financing activities	(9,854)	1,753
Effect of exchange rate changes on cash and cash equivalents	(157)	(497)
Less: net decrease in cash classified within assets held for sale	0	(7,545)
Net decrease in cash, cash equivalents and restricted cash	(12,693)	(24,074)
Cash, cash equivalents and restricted cash at beginning of period	102,518	116,252
Cash, cash equivalents and restricted cash at end of period	89,825	92,178
Non-cash investing and financing activities during the period:
Property, plant and equipment received and accrued in accounts payable and other liabilities	$ 28,986	$ 24,997