| 2013 | 2012 | |||||||
| Deferred tax assets: | ||||||||
| Compensated absences and severance, principally due to accruals for financial reporting purposes | $ | 150,000 | $ | 99,000 | ||||
| Stock-based compensation expense | 1,259,000 | 1,202,000 | ||||||
| Accounts receivable, principally due to allowance for doubtful accounts and sales returns | 78,000 | 78,000 | ||||||
| Property and equipment, principally due to differences in depreciation | 106,000 | 253,000 | ||||||
| Intangible assets | 464,000 | 360,000 | ||||||
| Inventories | 91,000 | 88,000 | ||||||
| Domestic net operating losses | 9,089,000 | 7,491,000 | ||||||
| Software development costs | - | - | ||||||
| Alternative minimum tax | 438,000 | 438,000 | ||||||
| Other | 61,000 | 66,000 | ||||||
| Deferred tax assets | 11,736,000 | 10,075,000 | ||||||
| Valuation allowance | (11,736,000 | ) | (10,075,000 | ) | ||||
| Net deferred tax assets | $ | 0 | $ | 0 | ||||