Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash Flows from Operating Activities
Net income (loss)	$ 8,842	$ (8,869)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	13,189	15,372
Non-cash interest expense	7,100	6,778
Deferred income taxes	17	191
Share-based compensation expense	7,605	6,620
Loss on extinguishment of debt		3,046
Asset impairment		281
Changes in operating assets and liabilities:
Accounts receivable and contract assets	(21,158)	(9,454)
Inventories and deferred cost of sales	(18,298)	(4,520)
Prepaid expenses and other current assets	4,489	(3,578)
Accounts payable and accrued expenses	14,046	5,820
Customer deposits and deferred revenue	3,334	3,470
Income taxes receivable and payable, net	449	93
Other, net	1,114	2,300
Net cash provided by (used in) operating activities	20,729	17,550
Cash Flows from Investing Activities
Capital expenditures	(9,082)	(1,957)
Proceeds from the sale of investments	130,398	103,630
Payments for purchases of investments	(156,020)	(100,265)
Proceeds from held for sale assets, net of costs to sell		9,503
Net cash provided by (used in) investing activities	(34,704)	10,911
Cash Flows from Financing Activities
Proceeds from issuance of 2025 Notes and 2027 Notes, net of issuance costs		121,946
Purchase of capped calls		(10,313)
Repurchase of 2023 Notes		(81,240)
Proceeds (net of tax withholdings) from option exercises and employee stock purchase plan	1,865	1,592
Restricted stock tax withholdings	(2,747)	(1,518)
Net cash provided by (used in) financing activities	(882)	30,467
Effect of exchange rate changes on cash and cash equivalents	(39)	(29)
Net increase (decrease) in cash, cash equivalents, and restricted cash	(14,896)	58,899
Cash, cash equivalents, and restricted cash - beginning of period	130,283	129,951
Cash, cash equivalents, and restricted cash - end of period	115,387	188,850
Supplemental Disclosure of Cash Flow Information
Interest paid	4,160	5,508
Net income taxes paid (refunds received)	(196)	66
Non-cash operating and financing activities
Capital expenditures included in accounts payable and accrued expenses	15,400	515
Net transfer of property, plant and equipment to inventory		526
Right-of-use assets obtained in exchange for lease obligations	$ 20,353	$ 913