11. Net Income (Loss) Per Share of Common Stock

We compute net income (loss) per share of common stock using the two-class method required for participating securities. Prior to the date of the initial public offering, we considered all series of our convertible preferred stock to be participating securities due to their non-cumulative dividend rights. Additionally, we consider shares issued upon the early exercise of options subject to repurchase and unvested restricted shares to be participating securities, because holders of such shares have non-forfeitable dividend rights in the event we declare a dividend for common shares. In accordance with the two-class method, net income allocated to these participating securities, which include participation rights in undistributed net income, is subtracted from net income (loss) to determine total net income (loss) to be allocated to common stockholders.

Basic net income (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period. In computing diluted net income (loss) attributable to common stockholders, net income (loss) is re-allocated to reflect the potential impact of dilutive securities, including stock options, warrants, unvested restricted stock and unvested ZSUs. Diluted net income (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding, including potential dilutive securities. For periods in which we have generated a net loss or there is no income attributable to common stockholders, we do not include stock options, warrants and unvested ZSUs in our calculation of diluted net income (loss) per share, as the impact of these awards is anti-dilutive.

The following table sets forth the computation of basic and diluted net income (loss) per share of common stock (in thousands, except per share data):

	Year Ended December 31,
	2016									2015									2014
	Class			Class			Class			Class			Class			Class			Class			Class			Class
	A			B			C			A			B			C			A			B			C
BASIC:
Net income (loss) attributable to common stockholders	$	(92,988	)	$	(12,660	)	$	(2,525	)	$	(103,628	)	$	(15,153	)	$	(2,729	)	$	(189,732	)	$	(30,869	)	$	(5,300	)
Weighted-average common shares outstanding		755,460			102,850			20,517			779,071			113,923			20,517			734,493			119,499			20,517
Basic net income (loss) per share	$	(0.12	)	$	(0.12	)	$	(0.12	)	$	(0.13	)	$	(0.13	)	$	(0.13	)	$	(0.26	)	$	(0.26	)	$	(0.26	)
DILUTED:
Net income (loss) attributable to common stockholders-basic	$	(92,988	)	$	(12,660	)	$	(2,525	)	$	(103,628	)	$	(15,153	)	$	(2,729	)	$	(189,732	)	$	(30,869	)	$	(5,300	)
Reallocation of net income (loss) as a result of conversion of Class C shares to Class A shares		(2,525	)		—			—			(2,729	)		—			—			(5,300	)		—			—
Reallocation of net income (loss) as a result of conversion of Class B shares to Class A shares		(12,660	)		—			—			(15,153	)		—			—			(30,869	)		—			—
Net income (loss) attributable to common stockholders-diluted	$	(108,173	)	$	(12,660	)	$	(2,525	)	$	(121,510	)	$	(15,153	)	$	(2,729	)	$	(225,901	)	$	(30,869	)	$	(5,300	)
Weighted -average common shares- outstanding basic		755,460			102,850			20,517			779,071			113,923			20,517			734,493			119,499			20,517
Conversion of Class C to Class A common shares outstanding		20,517			—			—			20,517			—			—			20,517			—			—
Conversion of Class B to Class A common shares outstanding		102,850			—			—			113,923			—			—			119,499			—			—
Weighted-average common shares outstanding- diluted		878,827			102,850			20,517			913,511			113,923			20,517			874,509			119,499			20,517
Diluted net income (loss) per share	$	(0.12	)	$	(0.12	)	$	(0.12	)	$	(0.13	)	$	(0.13	)	$	(0.13	)	$	(0.26	)	$	(0.26	)	$	(0.26	)

The following weighted-average employee equity awards were excluded from the calculation of diluted net income (loss) per share because their effect would have been anti-dilutive for the periods presented (in thousands):

	Year Ended December 31,
	2016		2015		2014
Stock options and employee stock purchase plan		28,380		29,412		42,454
Restricted shares		3,899		8,716		12,624
ZSUs		61,183		63,764		59,141
Total		93,462		101,892		114,219