The computation of basic and diluted net loss per share for the periods indicated is as follows:

At December 31, 2016, 2015 and 2014, we were contingently obligated to pay $3.0 million, $8.8 million and $12.4 million, respectively, related to prior acquisitions.

Included in the computation of basic net loss per share for the years ended December 31, 2016, 2015 and 2014 were 53,335, 292,967 and 803,583 potentially dilutive shares, respectively, representing $0.6 million, $6.5 million and $11.7 million, respectively, of the total contingent obligation related to shares we unconditionally agreed to issue.

Additionally, we were contingently obligated to pay $0.8 million, $0.5 million and $0.7 million, which may be settled, at our option, in either cash or an equivalent amount of common shares based upon their then-current market value, if certain performance criteria had been met. The equivalent amount of common shares have been excluded from the computation of diluted net loss per share for the years ended December 31, 2016, 2015 and 2015, as they were antidilutive.

At December 31, 2016, 2015 and 2014, 27,828, 31,483 and 41,438 outstanding options, respectively, with an average exercise price of $44.76, $43.64 and $42.90, respectively, were not recognized in the diluted earnings per share calculation as they were antidilutive.