Treasury Stock	9 Months Ended
Sep. 30, 2016
Treasury Stock [Abstract]
Treasury Stock [Text Block]	Treasury Stock In July 2010, our Board of Directors approved a common stock purchase plan to purchase up to $40.0 million of our common stock. This plan has no expiration date. For the nine months ended September 30, 2016 we purchased 174,885 shares of our common stock for $15.4 million, including commissions. As of September 30, 2016, the remaining authorized amount under this purchase plan is approximately $7.2 million. As of September 30, 2016, all of the treasury stock has been used to issue shares for stock option exercises, restricted stock grants and employee stock purchase plan stock purchases. Additionally, for the nine months ended September 30, 2016, we withheld 19,717 shares of our common stock from employee vested restricted stock units in consideration for $1.8 million in payments made on the employee's behalf for their minimum statutory income tax withholding obligations.

Treasury Stock

In July 2010, our Board of Directors approved a common stock purchase plan to purchase up to $40.0 million of our common stock. This plan has no expiration date. For the nine months ended September 30, 2016 we purchased 174,885 shares of our common stock for $15.4 million, including commissions. As of September 30, 2016, the remaining authorized amount under this purchase plan is approximately $7.2 million. As of September 30, 2016, all of the treasury stock has been used to issue shares for stock option exercises, restricted stock grants and employee stock purchase plan stock purchases.

Additionally, for the nine months ended September 30, 2016, we withheld 19,717 shares of our common stock from employee vested restricted stock units in consideration for $1.8 million in payments made on the employee's behalf for their minimum statutory income tax withholding obligations.