| 
           6. Stock-Based Compensation (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
| 
           Sep. 30, 2013 
         | 
        
           Sep. 30, 2012 
         | 
        
           Sep. 30, 2013 
         | 
        
           Sep. 30, 2012 
         | 
      |
| Total stock-based compensation | $ 296 | $ 372 | $ 483 | $ 680 | 
| 
           Cost of revenues 
         | 
        ||||
| Total stock-based compensation | 30 | 34 | 56 | 66 | 
| 
           Research and development 
         | 
        ||||
| Total stock-based compensation | 45 | 63 | 78 | 130 | 
| 
           Selling general and administrative 
         | 
        ||||
| Total stock-based compensation | $ 221 | $ 275 | $ 349 | $ 484 |