Net Loss Per Common Share (Details) - shares shares in Thousands	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	10,342	8,418
Common shares under option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	5,696	3,772
Convertible senior notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	4,646	4,646

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration