10. STOCK-BASED COMPENSATION - Stock option activities (Details)	6 Months Ended
	Sep. 30, 2022 $ / shares shares
STOCK-BASED COMPENSATION
Shares available for grant, Beginning	4,535,663
Granted (in shares)	(750,803)
Forfeited (in shares)	279,450
Shares available for grant, Ending	4,064,310
Number of Shares Underlying Options Outstanding
Balance at the beginning of the period (in shares)	8,590,675
Granted (in shares)	750,803
Forfeited (in shares)	(736,517)
Balance at the end of the period (in shares)	8,604,961
Options vested and exercisable (in shares)	5,625,224
Options vested and expected to vest (in shares)	8,499,457
Weighted Average Remaining Contractual Life
Options weighted average remaining contractual life	5 years 6 months 21 days
Options vested and expected to vest	5 years 6 months 3 days
Options vested and exercisable	3 years 11 months 26 days
Weighted Average Exercise Price
Balance at the beginning of the period (in dollars per share) | $ / shares	$ 6.07
Granted (in dollars per share) | $ / shares	4.01
Forfeited (in dollars per share) | $ / shares	5.53
Balance at the end of the period (in dollars per share) | $ / shares	5.94
Options vested and exercisable (in dollars per share) | $ / shares	6.00
Options vested and expected to vest (in dollars per share) | $ / shares	$ 5.94