Stock Incentive Plan - Summary of Stock Options Outstanding under Company's Equity Plans (Detail)	12 Months Ended
	Jul. 31, 2016 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options Outstanding | shares	4,639,092
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	7 years 1 month 24 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 7.24
Number of Options Exercisable | shares	2,372,431
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 4.27
$0.46 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 0.46
Number of Options Outstanding | shares	216,420
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	4 years 9 months 26 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 0.46
Number of Options Exercisable | shares	216,420
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.46
$0.61 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 0.61
Number of Options Outstanding | shares	21,707
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	2 years 6 months
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 0.61
Number of Options Exercisable | shares	21,707
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.61
$0.68 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 0.68
Number of Options Outstanding | shares	490,335
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	5 years 8 months 1 day
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 0.68
Number of Options Exercisable | shares	455,795
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.68
$1.06 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 1.06
Number of Options Outstanding | shares	436,699
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	5 months 12 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 1.06
Number of Options Exercisable | shares	436,699
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 1.06
$1.52 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 1.52
Number of Options Outstanding | shares	89,895
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	6 years 1 month 17 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 1.52
Number of Options Exercisable | shares	86,859
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 1.52
$1.75 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 1.75
Number of Options Outstanding | shares	105,131
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	6 years 7 months 24 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 1.75
Number of Options Exercisable | shares	89,002
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 1.75
$3.65 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 3.65
Number of Options Outstanding | shares	84,238
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	6 years 10 months 24 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 3.65
Number of Options Exercisable | shares	61,775
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 3.65
$4.10 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 4.10
Number of Options Outstanding | shares	633,700
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	7 years 2 months 1 day
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 4.10
Number of Options Exercisable | shares	471,529
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 4.10
$4.26 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 4.26
Number of Options Outstanding | shares	38,948
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	7 years 4 months 17 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 4.26
Number of Options Exercisable | shares	25,050
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 4.26
$7.37 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 7.37
Number of Options Outstanding | shares	98,380
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	7 years 7 months 6 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 7.37
Number of Options Exercisable | shares	59,751
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 7.37
$7.41 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 7.41
Number of Options Outstanding | shares	527,050
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 29 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 7.41
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$7.70 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 7.70
Number of Options Outstanding | shares	54,450
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 7 months 17 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 7.70
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$8.05 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 8.05
Number of Options Outstanding | shares	62,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 4 months 17 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 8.05
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$8.20 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 8.20
Number of Options Outstanding | shares	57,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 5 months 16 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 8.20
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$8.32 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 8.32
Number of Options Outstanding | shares	37,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 1 month 17 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 8.32
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$8.37 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 8.37
Number of Options Outstanding | shares	42,100
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 5 months 23 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 8.37
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$9.12 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 9.12
Number of Options Outstanding | shares	64,568
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	7 years 10 months 2 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 9.12
Number of Options Exercisable | shares	36,452
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 9.12
$9.60 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 9.60
Number of Options Outstanding | shares	18,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 8 months 19 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 9.60
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$10.41 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 10.41
Number of Options Outstanding | shares	100,100
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 18 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 10.41
Number of Options Exercisable | shares	51,795
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 10.41
$10.78 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 10.78
Number of Options Outstanding | shares	62,250
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 2 months 23 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 10.78
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$10.86 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 10.86
Number of Options Outstanding | shares	16,700
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 10 months 24 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 10.86
Number of Options Exercisable | shares	5,300
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 10.86
$11.96 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 11.96
Number of Options Outstanding | shares	25,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 11 months 19 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 11.96
Number of Options Exercisable | shares	0
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 0.00
$12.69 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 12.69
Number of Options Outstanding | shares	307,701
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 2 months 27 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 12.69
Number of Options Exercisable | shares	127,500
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 12.69
$12.96 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 12.96
Number of Options Outstanding | shares	447,100
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 10 months 21 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 12.96
Number of Options Exercisable | shares	625
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 12.96
$13.68 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 13.68
Number of Options Outstanding | shares	102,338
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 3 months 18 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 13.68
Number of Options Exercisable | shares	44,394
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 13.68
$15.88 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 15.88
Number of Options Outstanding | shares	153,172
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 15.88
Number of Options Exercisable | shares	66,913
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 15.88
$17.56 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price (usd per share)	$ 17.56
Number of Options Outstanding | shares	347,110
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 7 months 21 days
Options Outstanding, Weighted-Average Exercise Price per Share (usd per share)	$ 17.56
Number of Options Exercisable | shares	114,865
Options Exercisable, Weighted-Average Exercise Price Per Share (usd per share)	$ 17.56