The following table presents details of stock-based compensation expense included in each functional line item in the consolidated statements of operations above:
| Three Months Ended January 31, | Twelve Months Ended January 31, | ||||||||||||||
| 2021 | 2020 | 2021 | 2020 | ||||||||||||
| (unaudited, in thousands) | |||||||||||||||
| Stock-based compensation: | |||||||||||||||
| Cost of revenue | $ | 347 | $ | 262 | $ | 1,328 | $ | 1,184 | |||||||
| Research and development | 11,501 | 10,536 | 42,903 | 41,842 | |||||||||||
| Selling, general and administrative | 6,879 | 6,105 | 25,903 | 23,845 | |||||||||||
| Total stock-based compensation | $ | 18,727 | $ | 16,903 | $ | 70,134 | $ | 66,871 | |||||||
