(18)NET INCOME PER SHARE

The following table sets forth the computation of basic and diluted shares for the periods indicated (in thousands):


	Year Ended December 31,
	2017	2016	2015

Shares used in basic earnings per share calculation	45,826	47,423	48,370
Effect of dilutive securities:
Stock options	10	10	275
Restricted stock units	536	286	338
Performance-based restricted stock units	10	17	28
Total effects of dilutive securities	556	313	641
Shares used in dilutive earnings per share calculation	46,382	47,736	49,011

For the years ended December 31, 2017, 2016 and 2015, zero, 0.1 million and 0.1 million, respectively, of options to purchase shares of common stock were outstanding but not included in the computation of diluted net income per share because the exercise price exceeded the value of the shares and the effect would have been anti-dilutive. For the years ended December 31, 2017, 2016 and 2015, restricted stock units of 0.0 million, 0.1 million, and 0.4 million, respectively, were outstanding but not included in the computation of diluted net income per share because the effect would have been anti-dilutive. For the years ended December 31, 2017, 2016 and 2015, there were no performance-based restricted stock units outstanding but not included in the computation of diluted net income per share.