Share-Based Compensation - Stock Option Activity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Stock option activity
Options outstanding (in shares)	511,019
Options exercised (in shares)	(44,350)
Options cancelled (in shares)	(4,040)
Options outstanding (in shares)	462,629
Options outstanding, weighted average remaining contractual term (in years)	3 years 9 months 7 days
Options outstanding, aggregate intrinsic value	$ 155
Options vested or expected to vest (in shares)	446,395
Options vested or expected to vest, weighted average remaining contractual term (in years)	3 years 7 months 30 days
Options vested or expected to vest, aggregate intrinsic value	144
Options exercisable (in shares)	390,829
Options exercisable, weighted average remaining contractual term (years)	3 years
Options exercisable, aggregate intrinsic value	$ 75
Stock option activity, weighted average exercise price
Options Outstanding, weighted average exercise price (in dollars per share)	$ 8.56
Options exercised, weighted average exercise price (in dollars per share)	$ 5.42
Options canceled, weighted average exercise price (in dollars per share)	$ 10.34
Options Outstanding, weighted average exercise price (in dollars per share)	$ 8.84
Options vested or expected to vest, weighted average exercise price (in dollars per share)	$ 8.94
Options exercisable, weighted average exercise price (in dollars per share)	$ 9.41