Stock-Based Compensation (Details) (USD $)	102 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2012 Employee stock purchase plan	Jun. 30, 2012 Stock options	Jun. 30, 2012 2012 Employee Incentive Plan	May 31, 2012 2012 Employee Incentive Plan	Dec. 31, 2011 Prior Plans
Information related to stock-based compensation
Shares of common stock approved and authorized for issuance	2,025,000			6,500,000
Additional number of shares of common stock approved and authorized for issuance					12,667,411
Reduction in number of shares 2012 plan reserve for each stock option and SAR granted			1
Reduction in number of shares 2012 plan reserve for each stock award other than option and SAR granted			1.45
Shares remaining available for issuance	476,977		5,037,262
Stock issued during period (in shares)	1,548,023
Cumulative average sale price per share as of the period end (in dollars per share)	$ 10.53
Maximum term for stock options		10 years
Vesting term for stock option		4 years
Percentage of stock options to be vested at end of year one		25.00%
Percentage of stock options to be vested monthly over remaining three years		75.00%