Net Income Per Share - Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net income	$ 180,366	$ 138,431
Denominator:
Weighted-average shares used in computing net income per share, basic (in shares)	76,306	76,264
Add weighted-average effect of dilutive securities:
Stock options and RSUs (in shares)	3,279	3,675
Employee stock purchase plan (in shares)	38	0
Weighted-average shares used in computing net income per share, diluted (in shares)	79,623	79,939
Net income per share:
Basic (in dollars per share)	$ 2.36	$ 1.82
Diluted (in dollars per share)	$ 2.27	$ 1.73