Stockholders' Equity - Additional Information (Detail) - $ / shares |
Apr. 30, 2017 |
Apr. 30, 2016 |
---|---|---|
Class Of Stock [Line Items] | ||
Ordinary shares, par value | $ 0.0016 | $ 0.0016 |
Common stock, par value | $ 0.001 | $ 0.001 |
2017 Employee Stock Purchase Plan [Member] | ||
Class Of Stock [Line Items] | ||
Common stock available for issuance | 100,000 | |
Series B Convertible Preferred Stock [Member] | ||
Class Of Stock [Line Items] | ||
Preferred shares, par value | $ 0.0016 | |
Series A Convertible Preferred Stock [Member] | ||
Class Of Stock [Line Items] | ||
Preferred shares, par value | $ 0.0016 |