Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Deferred Tax Asset
-URI http://asc.fasb.org/extlink&oid=6510090

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Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jan. 01, 2017	Dec. 31, 2016	Dec. 31, 2015
Recent Accounting Pronouncements
Deferred tax assets		$ 72,268	$ 75,434
Deferred tax valuation allowance		$ 72,268	$ 75,434
ASU No. 2016-09 Compensation - Stock Compensation \| Forecast
Recent Accounting Pronouncements
Deferred tax assets	$ 13,100
Deferred tax valuation allowance	$ 13,100