NET INCOME PER SHARE

Basic net income per share is computed using the weighted-average number of outstanding shares of common stock during the period. Diluted net income per share is computed using the weighted-average number of outstanding shares of common stock and, when dilutive, potential shares of common stock outstanding during the period. Potential common shares consist of the incremental shares of common stock issuable upon the exercise of stock options, shares issuable upon the vesting of RSUs and, to a lesser extent, purchase rights related to the ESPP.

The following table presents the calculation of basic and diluted net income per share (in thousands, except per share data):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Basic net income per share:
Net income	$	14,986	$	8,030	$	23,404	$	11,874
Shares used in computation:
Weighted-average common shares outstanding	84,008		82,259		83,865		81,041
Basic net income per share attributable to common stockholders	$	0.18	$	0.10	$	0.28	$	0.15



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Diluted net income per share
Net income	14,986		8,030		23,404		11,874
Shares used in computation:
Weighted-average common shares outstanding	84,008		82,259		83,865		81,041
Stock options	3,011		3,253		3,096		3,179
Restricted stock units	1,656		1,921		2,240		1,877
Employee stock purchase program	49		—		70		—
Number of shares used in diluted calculation	88,724		87,433		89,271		86,097
Diluted net income per share attributable to common stockholders	$	0.17	$	0.09	$	0.26	$	0.14

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



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
Stock options	1,694	1,793	1,681	1,911
Restricted stock units	591	871	106	978