Income Taxes - Summary of Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation Allowance
Valuation allowance at beginning of year	$ 190,174	$ 161,660	$ 131,985
Increase (decrease) in valuation allowance as a result of mergers and acquisitions, net	(1,416)	1,228	914
Increase in valuation allowance as a result of current year operations	67,549	28,035	28,761
Decrease in valuation allowance as a result of foreign currency translation adjustment	(142)	(749)	0
Valuation allowance at end of year	$ 256,165	$ 190,174	$ 161,660

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32537-109319

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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- Definition

Change in the valuation allowance for deferred tax assets as a result of current year operations.

+ References

No definition available.

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- Definition

Change in the valuation allowance for deferred tax assets as a result of mergers and acquisitions, net.

+ References

No definition available.

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- Definition

Change in the valuation allowance for deferred tax assets as a result of foreign currency translation adjustments.

+ References

No definition available.

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