Diluted net income (loss) per share attributable to common stockholders is based upon the weighted-average number of shares of common stock outstanding and the weighted-average number of shares outstanding assuming the issuance of common stock upon exercise of stock options, warrants to purchase common stock, and the vesting of restricted stock grants per ASC 260, “Earnings Per Share.”



	Twelve Months Ended December 31
	2014	2013	2012
Weighted average number of shares outstanding:
Common stock	20,595,422	20,190,245	20,043,862
Common stock equivalents-stock options, grants	37,033	195,310	75,114
Diluted shares outstanding	20,632,455	20,385,555	20,118,976