Note 4 - Revenue Recognition (Details Textual) - USD ($) |
1 Months Ended | 3 Months Ended | 9 Months Ended | |
|---|---|---|---|---|
Oct. 31, 2019 |
Mar. 31, 2020 |
Mar. 31, 2020 |
Jun. 30, 2019 |
|
| Contract with Customer, Asset, after Allowance for Credit Loss, Current, Total | $ 7,100,000 | $ 7,100,000 | $ 8,000,000 | |
| Contract with Customer, Liability, Total | 50,200,000 | 50,200,000 | $ 56,700,000 | |
| Contract with Customer, Liability, Revenue Recognized | $ 1,100,000 | $ 54,700,000 | ||
| Annual Fee Per Member [Member] | ||||
| Membership, Annual Fee Amount Per Member | $ 100 | |||
| Contract with Customer, Satisfaction of Performance Obligation Period (Year) | 1 year |