CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net loss	$ (67,836)	$ (52,613)
Adjustments to reconcile net loss to cash used in operating activities
Depreciation and amortization	57,162	62,050
Equity-based compensation expense	5,168	9,116
Amortization of deferred financing costs	0	246
Deferred tax benefit	0	(20,320)
Provision for bad debts	41	371
(Gain) loss on disposal of assets	452	(1,262)
Changes in fair value of investments	(417)	(1,474)
Realized loss on sale of investment	0	478
Unrealized (gain) loss on derivatives	(765)	730
Other	0	(1,876)
Changes in operating assets and liabilities
Accounts receivable	(21,712)	(6,697)
Inventories	(1,461)	5,627
Other current assets	2,042	3,102
Other assets	324	1,745
Accounts payable and accrued liabilities	(10,192)	4,400
Deferred revenue	(424)	(7,707)
Other non-current liabilities	(244)	(3,383)
Net cash used in operating activities	(37,862)	(7,467)
Cash flows from investing activities
Purchases of property, plant and equipment and intangibles	(11,265)	(15,240)
Proceeds from sale of assets	1,755	2,200
Proceeds from sale of investments	56,946	11,499
Purchase of investments	(42,279)	(118)
Net cash (used in) provided by investing activities	5,157	(1,659)
Cash flows from financing activities
Repayments of borrowings	(2,921)	(154)
Dividends paid on common stock	0	(33,426)
Net treasury shares withheld for taxes	(1,217)	(2,249)
Proceeds from the issuance of ESPP shares	562	1,266
Deferred financing costs	(48)	0
Net cash used in financing activities	(3,624)	(34,563)
Effect of exchange rate changes on cash	2,078	(887)
Net decrease in cash and cash equivalents	(34,251)	(44,576)
Cash and cash equivalents at beginning of period	213,015	319,526
Cash and cash equivalents at end of period	178,764	274,950
Non-cash transactions:
Change in accounts payable and accrued liabilities related to capital expenditures	(3,460)	2,901
Net transfers from inventory to property, plant and equipment	$ (2,028)	$ (1,358)