Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows from Operating Activities
Net income (loss)	$ (8,290)	$ (45,862)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	23,021	25,838
Non-cash interest expense	10,282	9,418
Deferred income taxes	330	20
Share-based compensation expense	9,562	11,528
Loss on extinguishment of debt	3,046
Asset impairment	281
Provision for bad debts	140
Changes in operating assets and liabilities:
Accounts receivable and contract assets	(30,677)	(16,308)
Inventories and deferred cost of sales	(10,336)	17,921
Prepaid expenses and other current assets	(982)	(1,276)
Accounts payable and accrued expenses	11,130	(16,000)
Customer deposits and deferred revenue	16,728	(6,705)
Income taxes receivable and payable, net	61	(593)
Other, net	3,295	(986)
Net cash provided by (used in) operating activities	27,591	(23,005)
Cash Flows from Investing Activities
Capital expenditures	(3,331)	(8,189)
Proceeds from the sale of investments	139,531	102,230
Payments for purchases of investments	(185,576)	(148,664)
Proceeds from held for sale assets, net of costs to sell	9,503	645
Net cash provided by (used in) investing activities	(39,873)	(53,978)
Cash Flows from Financing Activities
Proceeds from issuance of 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	2,428	2,609
Restricted stock tax withholdings	(2,217)	(2,771)
Net cash provided by (used in) financing activities	30,604	(162)
Effect of exchange rate changes on cash and cash equivalents	(21)	9
Net increase (decrease) in cash, cash equivalents, and restricted cash	18,301	(77,136)
Cash, cash equivalents, and restricted cash - beginning of period	129,951	213,082
Cash, cash equivalents, and restricted cash - end of period	148,252	135,946
Supplemental Disclosure of Cash Flow Information
Interest paid	8,989	9,401
Income taxes paid	248	2,835
Non-cash operating and financing activities
Net transfer of property, plant and equipment to inventory	1,624	4,074
Right-of-use assets obtained in exchange for lease obligations	$ 951	$ 516