Net loss per share - Computation of diluted net loss per share attributable to common stockholders (Details) - shares	12 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding (in shares)	17,294,340	14,323,996
Options to purchase common stock
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding (in shares)	11,785,458	10,214,878
Unvested restricted and performance stock units
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding (in shares)	5,508,882	3,611,774
Warrants to purchase common stock
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding (in shares)	0	497,344