Net Income (Loss) Per Share of Common Stock - Schedule of Computation of Basic and Diluted Net Income (Loss) Per Share of Common Stock (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic
Net income (loss) attributable to common stockholders – basic	$ 41,925	$ 15,457	$ 26,639
Weighted-average common shares outstanding – basic	938,709	862,460	869,067
Net income (loss) per share attributable to common stockholders	$ 0.04	$ 0.02	$ 0.03
Diluted
Weighted-average common shares outstanding – basic	938,709	862,460	869,067
Weighted-average common shares outstanding – diluted	974,020	889,584	897,165
Net income (loss) per share attributable to common stockholders – diluted	$ 0.04	$ 0.02	$ 0.03
Common Class A [Member]
Basic
Net income (loss) attributable to common stockholders – basic	$ 41,925	$ 15,457	$ 23,795
Weighted-average common shares outstanding – basic	938,709	862,460	776,625
Net income (loss) per share attributable to common stockholders	$ 0.04	$ 0.02	$ 0.03
Diluted
Net income (loss) attributable to common stockholders – basic	$ 41,925	$ 15,457	$ 23,795
Net income (loss) attributable to common stockholders – diluted			$ 26,628
Weighted-average common shares outstanding – basic	938,709	862,460	776,625
Weighted-average common shares outstanding – diluted	974,020	889,584	897,165
Net income (loss) per share attributable to common stockholders – diluted	$ 0.04	$ 0.02	$ 0.03
Common Class A [Member] | Stock Options and Employee Stock Purchase Plan [Member]
Diluted
Weighted-average effect of dilutive securities	12,960	10,958	9,879
Common Class A [Member] | Restricted Stock Units (ZSUs) [Member]
Diluted
Weighted-average effect of dilutive securities	22,351	15,212	16,935
Common Class A [Member] | Performance Based Restricted Stock Units (ZSUs) [Member]
Diluted
Weighted-average effect of dilutive securities		954	1,284
Common Class A [Member] | Class C Convert to Class A [Member]
Diluted
Reallocation of net income (loss) as a result of common stock class conversion			$ 629
Conversion of common stock class			20,517
Common Class A [Member] | Class B Convert to Class A [Member]
Diluted
Reallocation of net income (loss) as a result of common stock class conversion			$ 2,204
Conversion of common stock class			71,925
Common Class B [Member]
Basic
Net income (loss) attributable to common stockholders – basic			$ 2,204
Weighted-average common shares outstanding – basic			71,925
Net income (loss) per share attributable to common stockholders			$ 0.03
Diluted
Net income (loss) attributable to common stockholders – basic			$ 2,204
Reallocation of net income (loss) to Class B and Class C shares			180
Net income (loss) attributable to common stockholders – diluted			$ 2,384
Weighted-average common shares outstanding – basic			71,925
Weighted-average common shares outstanding – diluted			80,315
Net income (loss) per share attributable to common stockholders – diluted			$ 0.03
Common Class B [Member] | Stock Options and Employee Stock Purchase Plan [Member]
Diluted
Weighted-average effect of dilutive securities			8,390
Common Class C [Member]
Basic
Net income (loss) attributable to common stockholders – basic			$ 629
Weighted-average common shares outstanding – basic			20,517
Net income (loss) per share attributable to common stockholders			$ 0.03
Diluted
Net income (loss) attributable to common stockholders – basic			$ 629
Reallocation of net income (loss) to Class B and Class C shares			(20)
Net income (loss) attributable to common stockholders – diluted			$ 609
Weighted-average common shares outstanding – basic			20,517
Weighted-average common shares outstanding – diluted			20,517
Net income (loss) per share attributable to common stockholders – diluted			$ 0.03