Quarterly Results of Operations (unaudited) - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2017	Dec. 31, 2017
Quarterly Results of Operations (unaudited)
Inventory Write-down	$ 6.2	$ 6.2
Tax benefit relating to reversal of a valuation allowance on deferred tax assets	$ 81.6

Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=66092785&loc=d3e4542-108314

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 35
-Paragraph 1C
-URI http://asc.fasb.org/extlink&oid=68049868&loc=SL66093883-108312

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 35
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=68049868&loc=SL66093879-108312

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