Related party (Narrative) (Details) - $ / shares |
Jan. 31, 2019 |
Jul. 19, 2018 |
Apr. 30, 2018 |
|---|---|---|---|
| Related Party Transaction [Line Items] | 听 | 听 | 听 |
| Per share price | $ 0.001 | 听 | $ 0.001 |
| Common Stock [Member] | 听 | 听 | 听 |
| Related Party Transaction [Line Items] | 听 | 听 | 听 |
| Treasury stock repurchased | 听 | 1,000,000 | 听 |
| Per share price | 听 | $ 7.40 | 听 |
| Sale of common stock per share price | 听 | $ 7.40 | 听 |
| X | ||||||||||
- Definition Face amount or stated value per share of common stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Per share or per unit amount of equity securities issued. No definition available.
|
| X | ||||||||||
- Definition Number of previously issued common shares repurchased by the issuing entity and held in treasury. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Details
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