Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net loss		$ (29,420)	$ (25,008)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		3,893	4,278
Share-based compensation expense		3,666	2,942
Other		3,105	(255)
Cash provided (used) due to changes in operating assets and liabilities:
Accounts and other receivables		22,113	65,323
Inventory		(3,750)	4,056
Prepaid expenses and other assets		5,428	4,771
Accounts payable		(7,775)	(36,299)
Accrued payroll and related expenses and other liabilities		(14,440)	(2,501)
Customer contract liabilities		(3,402)	(18,322)
Net cash used in operating activities		(20,582)	(1,015)
Investing activities:
Cash received in strategic transaction		0	1,584
Purchases of property and equipment		(3,659)	(2,188)
Net cash used in investing activities		(3,659)	(604)
Financing activities:
Purchase of employee restricted shares to fund related statutory tax withholding		(141)	(158)
Proceeds from exercises of stock options		829	1,538
Net cash provided by financing activities		688	1,380
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash		221	166
Net decrease in cash, cash equivalents and restricted cash		(23,332)	(73)
Cash, cash equivalents and restricted cash:
Beginning of period		245,764	140,320
End of period		222,432	140,247
Cash and cash equivalents		205,121
Restricted cash	[1]	1,281
Long-term restricted cash	[1]	16,030
Supplemental disclosure of cash flow information:
Cash paid (refunded) for income taxes		(292)	301
Non-cash investing and financing activities:
Inventory transfers to fixed assets and service spares		$ 404	$ 1,613

[1] Restricted cash primarily associated with certain letters of credit to secure customer prepayments and other customer related obligations.