Stockholders' Equity and Stock-based Compensation Expense (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs and Stock repurchase program [Line Items]
Stock-based compensation expense	$ 748,000	$ 809,000	$ 2,370,000	$ 2,334,000
Number of shares of common stock issued (in shares)			556,674
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock granted (in shares)			1,230,000
Unrecognized compensation expense, net of projected forfeitures	5,100,000		5,100,000
Period for Recognition			2 years 9 months 18 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock granted (in shares)			1,007,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock granted (in shares)			189,000
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock granted (in shares)			34,000
Original stock buyback program [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs and Stock repurchase program [Line Items]
Increase in the authorized amount under the stock repurchase plan			10,000,000
Modified stock buyback program [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs and Stock repurchase program [Line Items]
Amount authorized by the Board of Directors for stock repurchase program			20,000,000
Shares of common stock repurchased (in shares)	796,919
Value of common stock repurchased	7,600,000
Remaining amount available for the stock repurchase program			12,400,000
Cost of Revenue [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs and Stock repurchase program [Line Items]
Stock-based compensation expense	159,000	169,000	484,000	480,000
Sales and Marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs and Stock repurchase program [Line Items]
Stock-based compensation expense	182,000	177,000	579,000	476,000
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs and Stock repurchase program [Line Items]
Stock-based compensation expense	103,000	126,000	293,000	419,000
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs and Stock repurchase program [Line Items]
Stock-based compensation expense	$ 304,000	$ 337,000	$ 1,014,000	$ 959,000