Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	100,000,000us-gaap_CommonStockSharesAuthorized	100,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued (in shares)	43,511,093us-gaap_CommonStockSharesIssued	45,378,785us-gaap_CommonStockSharesIssued
Common stock, outstanding (in shares)	43,511,093us-gaap_CommonStockSharesOutstanding	45,378,785us-gaap_CommonStockSharesOutstanding

Face amount or stated value per share of common stock.

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

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