Summary of Significant Accounting Policies (Details 3) (Restricted common stock, Unvested)	9 Months Ended	12 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Restricted common stock \| Unvested
Other information
Shares of unvested restricted common stock granted to employees	0	0

Gross number of share options (or share units) granted during the period.

No definition available.

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