STOCK-BASED COMPENSATION (Details) (USD $)
|
12 Months Ended | 12 Months Ended | 12 Months Ended | 12 Months Ended | |||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Dec. 31, 2012
Options
|
Dec. 31, 2011
Options
|
Dec. 31, 2010
Options
|
Dec. 31, 2009
Options
|
Dec. 31, 2012
Restricted stock and restricted stock unit
|
Dec. 31, 2011
Restricted stock and restricted stock unit
|
Dec. 31, 2010
Restricted stock and restricted stock unit
|
Dec. 31, 2009
Restricted stock and restricted stock unit
|
Dec. 31, 2012
2000 Option Plan
|
Dec. 31, 2012
2000 Option Plan
Maximum
|
Dec. 31, 2012
2000 Option Plan
Minimum
|
Dec. 31, 2012
2000 Option Plan
Options
|
Dec. 31, 2012
2000 Option Plan
Restricted stock
|
Dec. 31, 2010
2000 Purchase Plan
|
Dec. 31, 2012
2010 Stock Plan
|
Dec. 31, 2012
2010 Stock Plan
Maximum
|
Dec. 31, 2012
2010 Stock Plan
Minimum
|
Dec. 31, 2012
2010 Stock Plan
Options
|
Dec. 31, 2012
2010 Stock Plan
Restricted stock
|
Dec. 31, 2012
2010 Purchase Plan
|
Dec. 31, 2011
2010 Purchase Plan
|
Dec. 31, 2010
2010 Purchase Plan
|
Dec. 31, 2012
2010 Purchase Plan
April 30, 2012
|
Dec. 31, 2012
2010 Purchase Plan
October 31, 2012
|
Dec. 31, 2012
2010 Purchase Plan
Maximum
|
Dec. 31, 2012
2010 Purchase Plan
Minimum
item
|
|
Stock-based compensation | |||||||||||||||||||||||||||||
Expiration period from the date of grant | 10 years | 10 years | |||||||||||||||||||||||||||
Vesting period | 1 year | 4 years | 3 years | 4 years | 3 years | ||||||||||||||||||||||||
Period by which all options to purchase common stock will accelerate upon an acquisition of the company | 1 year | 1 year | |||||||||||||||||||||||||||
Period from the completion of acquisition, during which if an employee is terminated without cause or for good reason, all awards then outstanding held by that employee will immediately become exercisable | 1 year | ||||||||||||||||||||||||||||
Shares outstanding | 6,181,996 | 6,453,644 | 6,217,199 | 5,912,019 | 4,889,933 | 54,000 | 1,292,063 | 759,955 | |||||||||||||||||||||
Shares unreleased | 813,955 | 401,490 | 263,630 | 40,000 | |||||||||||||||||||||||||
Number of hours per week of customary employment required to participate in the plan | 20 | ||||||||||||||||||||||||||||
Number of months of customary employment required to participate in the plan | 5 months | ||||||||||||||||||||||||||||
Percentage of employee's compensation to be deducted from the employee's pay | 15.00% | 1.00% | |||||||||||||||||||||||||||
Option exercise price, expressed as a percentage of fair market value | 85.00% | ||||||||||||||||||||||||||||
Maximum value of shares that an employee is permitted to purchase | $ 25,000 | ||||||||||||||||||||||||||||
Number of Shares | 58,709 | 63,611 | 51,857 | 115,468 | 34,336 | 29,275 | |||||||||||||||||||||||
Weighted Average Price per Share (in dollars per share) | $ 5.67 | $ 5.89 | |||||||||||||||||||||||||||
Shares available for future grant | 1,674,450 | 1,489,918 | 184,532 | ||||||||||||||||||||||||||
Proceeds from stock option exercise | $ 2,400,000 | $ 700,000 | $ 500,000 | $ 100,000 | $ 400,000 | $ 300,000 |