Share-Based Payments (Details)	12 Months Ended
	Dec. 31, 2012 item
2005 Plan | Stock option
Share-based payments
Maximum number of shares of common stock provided for issuance	2,000,000
Number of annual installments in which the awards would generally vest starting on the first anniversary of the date of grant	4
Contractual term	10 years
Period from the termination date of option in which the entity has the right and option to purchase the shares of common stock	180 days
2012 Plan
Share-based payments
Maximum number of shares of common stock provided for issuance	2,500,000
2012 Plan | Stock option
Share-based payments
Number of annual installments in which the awards would generally vest starting on the first anniversary of the date of grant	4