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
Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net loss from continuing operations	$ (35,202)	$ (30,180)
Shares used in per share calculation (in shares)	42,236	34,841
Net loss from continuing operations per share, basic and diluted (in dollars per share)	$ (0.83)	$ (0.87)

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

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