5. Net Income (Loss) per Share

Basic net income (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted average number of shares of common stock of the Company outstanding during the period. The Company computed net income (loss) per share of common stock using the treasury stock method for the three and nine months ended September 30, 2018 and September 30, 2017, respectively. Diluted net income (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period plus the impact of dilutive securities, to the extent that they are not anti-dilutive. The following table presents the calculation of basic and diluted net income (loss) per share for the Company’s common stock:


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017*		2018		2017*
Numerator:
Net income (loss) attributable to common stockholders, basic and diluted	$	10,416	$	6,165	$	(36,704)	$	1,889
Denominator:
Weighted average shares of common stock outstanding, basic		19,217,623		16,699,102		18,989,334		16,483,169
Denominator (diluted):
Weighted average shares of common stock outstanding		19,217,623		16,699,102		18,989,334		16,483,169
Effect of potential dilutive securities:
Weighted average dilutive effect of stock options		1,898,543		1,235,883		—		1,308,202
Weighted average dilutive effect of restricted shares		898,821		711,046		—		607,988
Weighted average dilutive effect of contingently issuable shares		273,886		—		—		—
Weighted average dilutive effect of common shares from warrants		—		—		—		12,441
Weighted average shares of common stock outstanding, diluted		22,288,873		18,646,031		18,989,334		18,411,800
Net income (loss) per share attributable to common stockholders, basic	$	0.54	$	0.37	$	(1.93)	$	0.11
Net income (loss) per share attributable to common stockholders, diluted	$	0.47	$	0.33	$	(1.93)	$	0.10

*As adjusted. See Note 3 for additional information.

The following potential common shares, presented based on amounts outstanding or shares contingently issuable for the nine months ended September 30, 2018, were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect:


		Nine Months Ended
		September 30,
		2018
Stock options to purchase common stock		2,566,855
Unvested restricted stock		1,063,681
Contingently issuable shares		142,679
		3,773,215