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,
	2016	2015	2014
Weighted average number of shares outstanding:
Common stock	20,737,903	20,665,792	20,595,422
Common stock equivalents-stock options, grants	46,839	71,879	37,033
Diluted shares outstanding	20,784,742	20,737,671	20,632,455