CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net loss	$ (64,568)	$ (19,514)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	22,658	24,721
Stock-based compensation expense	9,541	9,461
Impairments		7,719
Restructuring and other charges	22,465	34,902
Gain on sale of assets	(3,886)	(538)
Deferred income taxes	(993)	(2,116)
Changes in operating assets and liabilities:
Trade receivables, net	11,632	8,705
Unbilled receivables	25,961	(4,815)
Inventories, net	(6,680)	(38,475)
Prepaids and other assets	14,706	(23,185)
Accounts payable and accrued expenses	2,902	(1,169)
Other, net	0	2
Net cash provided by (used in) operating activities	33,738	(4,302)
Investing activities
Purchase of property, plant and equipment	(7,928)	(10,243)
Proceeds from sale of equipment	5,967	3,646
Net cash used in investing activities	(1,961)	(6,597)
Financing activities
Repurchase of common shares	(1,132)	(25,000)
Other	(113)	(176)
Net cash used in financing activities	(1,245)	(25,176)
Effect of exchange rate changes on cash activities	(1,315)	(3,700)
Increase (decrease) in cash and cash equivalents	29,217	(39,775)
Cash and cash equivalents at beginning of period	345,955	398,946
Cash and cash equivalents at end of period	$ 375,172	$ 359,171