Stockholders' Equity and Stock Option Plans - Share Based Awards Narrative (Details)
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12 Months Ended | 12 Months Ended | 12 Months Ended | ||||||||||||||||||||||||||||||
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Dec. 31, 2012
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May 08, 2007
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May 11, 2010
Director Stock Plan, 2010
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Dec. 31, 2012
Equity Plan, 2007
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Dec. 31, 2011
Equity Plan, 2007
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May 08, 2007
Equity Plan, 2007
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Dec. 31, 2012
Employee Stock Purchase Plan, 2007
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Jul. 01, 2007
Employee Stock Purchase Plan, 2007
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Dec. 31, 2011
Former 1999 Stock Option Plan
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Dec. 31, 2012
Officer and Employee
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Dec. 31, 2012
Nonemployee Director
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Dec. 31, 2005
Nonemployee Director
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Dec. 31, 2012
Nonemployee Director
Immediately Upon Grant
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Dec. 31, 2012
Nonemployee Director
Vesting Rate, Year One
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Dec. 31, 2012
Nonemployee Director
Vesting Rate, Year Two
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Dec. 31, 2012
Nonemployee Director
Vesting Rate, Year Three
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Dec. 31, 2012
Nonemployee Director
Vesting Rate Year Four
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Dec. 31, 2012
Common Stock
Director Stock Plan, 2010
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Dec. 31, 2011
Common Stock
Director Stock Plan, 2010
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Dec. 31, 2005
Prior to January 1, 2006
Stock options
Officer and Employee
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Dec. 31, 2005
Prior to January 1, 2006
Stock options
Officer and Employee
Immediately Upon Grant
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Dec. 31, 2005
Prior to January 1, 2006
Stock options
Officer and Employee
Vesting Rate, Year One
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Dec. 31, 2005
Prior to January 1, 2006
Stock options
Officer and Employee
Vesting Rate, Year Two
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Dec. 31, 2005
Prior to January 1, 2006
Stock options
Officer and Employee
Vesting Rate, Year Three
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Dec. 31, 2005
Prior to January 1, 2006
Stock options
Officer and Employee
Vesting Rate Year Four
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Dec. 31, 2012
Subsequent to January 1, 2006
Unvested restricted stock
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Dec. 31, 2012
Subsequent to January 1, 2006
Unvested restricted stock
Vesting Rate, Year One
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Dec. 31, 2012
Subsequent to January 1, 2006
Unvested restricted stock
Vesting Rate, Year Two
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Dec. 31, 2012
Subsequent to January 1, 2006
Unvested restricted stock
Vesting Rate, Year Three
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Dec. 31, 2012
Subsequent to January 1, 2006
Unvested restricted stock
Vesting Rate Year Four
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Dec. 31, 2012
Subsequent to January 1, 2006
Unvested restricted stock
Vesting Rate Year Five
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Dec. 31, 2012
Minimum
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Dec. 31, 2012
Maximum
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||||||||||||||||||||||||||||
Number of common shares approved to be issued in each plan | 500,000 | 150,000 | 200,000 | ||||||||||||||||||||||||||||||
Shares awarded in period from plan | 0 | 0 | 5,270 | 5,590 | |||||||||||||||||||||||||||||
Approved payroll deduction to purchase shares, percentage | 1.00% | 15.00% | |||||||||||||||||||||||||||||||
Discount from closing market price at end of each quarter | 5.00% | ||||||||||||||||||||||||||||||||
Number of shares available for future grants under plan | 135,850 | 298,159 | 195,316 | ||||||||||||||||||||||||||||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 0 | ||||||||||||||||||||||||||||||||
Vesting percentage | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | 20.00% | ||||||||||||||||||
Award vesting period | 4 years | 4 years | 5 years | ||||||||||||||||||||||||||||||
Expiration period of grants | 10 years | 7 years |