Net Loss Per Share - Reconciliation of Numerator and Denominators in Computing Net Loss per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net loss from continuing operations	$ (42,264)	$ (42,660)	$ (101,283)	$ (86,239)
Shares used in per share calculation (in shares)	39,242	25,431	36,485	25,024
Net loss from continuing operations per share, basic and diluted (in dollars per share)	$ (1.08)	$ (1.68)	$ (2.78)	$ (3.45)

Amount after tax of income (loss) from continuing operations attributable to the parent.

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