Capital Stock Capital Stock (Details) - USD ($)		12 Months Ended		33 Months Ended
	May. 20, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Apr. 10, 2013
Capital Stock
Authorized shares of capital stock		105,000,000		105,000,000
Authorized shares of common stock		100,000,000	100,000,000	100,000,000
Common stock, par value (usd per share)		$ 0.01	$ 0.01	$ 0.01
Authorized shares of preferred stock		5,000,000	5,000,000	5,000,000
Preferred stock, par value (usd per share)		$ 0.001	$ 0.001	$ 0.001
Common stock reserved for future issuance (shares)		2,853,000		2,853,000
Shares under the 2009 Stock Incentive Plan
Capital Stock
Common stock reserved for future issuance (shares)		2,805,000		2,805,000
Shares under the Employee Stock Purchase Plan
Capital Stock
Common stock reserved for future issuance (shares)		48,000		48,000
April 2013 Repurchase Program
Capital Stock
Common stock authorized for repurchase					$ 20,000,000.0
Repurchase of common stock	$ 1,600,000	$ 8,800,000		$ 10,400,000
Common stock repurchased and retired, shares	96,948			634,479
Additional Paid-in- Capital
Capital Stock
Repurchase of common stock		3,304,000	$ 770,000
Additional Paid-in- Capital | April 2013 Repurchase Program
Capital Stock
Repurchase of common stock	$ 600,000
Accumulated Deficit
Capital Stock
Repurchase of common stock		$ 5,498,000	$ 857,000
Accumulated Deficit | April 2013 Repurchase Program
Capital Stock
Repurchase of common stock	$ 1,000,000