5. Accounts Receivable
Accounts receivable at March 31, 2012 and 2011 consisted of the following (in thousands):
| March 31, | ||||||
| 2012 | 2011 | |||||
| Accounts receivable (billed) | $ | 16,240 | $ | 10,938 | ||
| Accounts receivable (unbilled) | 2,811 | 5,004 | ||||
| Less: Allowance for doubtful accounts | (52 | ) | (683 | ) | ||
| Accounts receivable, net | $ | 18,999 | $ | 15,259 | ||