Note 6 - Property and Equipment, Net (Details) - USD ($) $ in Thousands |
Nov. 30, 2015 |
May. 31, 2015 |
|---|---|---|
| Land [Member] | ||
| Property and Equipment, Gross | $ 235 | $ 250 |
| Building and Building Improvements [Member] | ||
| Property and Equipment, Gross | 2,324 | 2,494 |
| Leasehold Improvements [Member] | ||
| Property and Equipment, Gross | 26,101 | 25,639 |
| Construction in Progress [Member] | ||
| Property and Equipment, Gross | 2,714 | 6,897 |
| Furniture and Fixtures [Member] | ||
| Property and Equipment, Gross | 3,810 | 3,757 |
| Machinery and Equipment [Member] | ||
| Property and Equipment, Gross | 101,643 | 94,021 |
| Property and Equipment, Gross | 136,827 | 133,058 |
| Less accumulated depreciation | (64,601) | (59,484) |
| Property and equipment, net | $ 72,226 | $ 73,574 |