Recent Accounting Developments - Balance Sheet Impact (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Assets
Accounts receivable, trade	$ 130,596	$ 121,299	$ 113,416
Inventory	82,470	83,774	90,691
Contract costs	31,240	21,524	0
Liabilities
Accounts payable, trade	91,818		54,585
Accrued liabilities	67,152	71,325	71,116
Deferred revenue	8,859	8,046	4,858
Deferred income taxes	2,568	102,370	97,943
Other long-term liabilities	17,536		20,116
Equity
Additional paid-in capital	3,150,118		3,093,058
Accumulated deficit	(2,252,349)	(2,226,577)	$ (2,241,243)
Calculated under Revenue Guidance in Effect before Topic 606
Assets
Accounts receivable, trade	115,923
Inventory	97,463
Contract costs	0
Liabilities
Accounts payable, trade	91,776
Accrued liabilities	66,930
Deferred revenue	7,037
Deferred income taxes	2,329
Other long-term liabilities	17,514
Equity
Additional paid-in capital	3,140,754
Accumulated deficit	(2,271,558)
Adjustments Due to the Revenue Recognition Update | ASU 2014-09
Assets
Accounts receivable, trade	14,673	7,883
Inventory	(14,993)	(6,917)
Contract costs	31,240	21,524
Liabilities
Accounts payable, trade	42
Accrued liabilities	222	209
Deferred revenue	1,822	3,188
Deferred income taxes	239	4,427
Other long-term liabilities	22
Equity
Additional paid-in capital	9,364
Accumulated deficit	$ 19,209	$ 14,666