The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Stock-Based Compensation (Details)	1 Months Ended	3 Months Ended
Stock-Based Compensation (Details)	Jan. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Stock-based compensation
Stock options issued (in shares)		2,719,000
2011 Plan
Stock-based compensation
Shares of common stock available for grant (in shares)		1,900,000	1,300,000
Additional common stock available for issuance (in shares)	3,400,000
Stock options issued (in shares)		2,700,000