| 3. BALANCE SHEET COMPONENTS   The components of certain balance sheet amounts are as follows (in thousands):   
|  |  | March 31, 2024 |  |  | December 31, 2023 |  |  
| Cash, cash equivalents and restricted cash: |  |  |  |  |  |  |  |  |  
| Cash |  | $ | 8,954 |  |  | $ | 8,971 |  |  
| Cash equivalents |  |  | 16,871 |  |  |  | 47,207 |  |  
|  |  |  | 25,825 |  |  |  | 56,178 |  |  
| Restricted cash |  |  | 37 |  |  |  | 39 |  |  
|  |  | $ | 25,862 |  |  | $ | 56,217 |  |  
| Inventories: |  |  |  |  |  |  |  |  |  
| Finished goods |  | $ | 4,247 |  |  | $ | 3,473 |  |  
| Raw materials |  |  | 723 |  |  |  | 855 |  |  
| Reserve for obsolescence |  |  | (71 | ) |  |  | (35 | ) |  
|  |  | $ | 4,899 |  |  | $ | 4,293 |  |  
| Other accrued expenses: |  |  |  |  |  |  |  |  |  
| Sales returns |  | $ | 96 |  |  | $ | 81 |  |  
| Employee-related expense |  |  | 478 |  |  |  | 668 |  |  
| Warehousing, inventory-related and other |  |  | 783 |  |  |  | 421 |  |  
|  |  | $ | 1,357 |  |  | $ | 1,170 |  |  
| Deferred revenue: |  |  |  |  |  |  |  |  |  
| Unshipped product and unredeemed product vouchers |  | $ | 5,480 |  |  | $ | 4,417 |  |  
| Auto ship advances |  |  | 1,694 |  |  |  | 1,749 |  |  
|  |  | $ | 7,174 |  |  | $ | 6,166 |  |    |