Stock-Based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Mar. 31, 2025
Options
Outstanding at beginning of period (in shares)	3,239,642
Granted (in shares)	1,673,627
Exercised (in shares)	(211)	0
Forfeited (in shares)	(34,855)
Expired (in shares)	(2,337)
Outstanding at end of period (in shares)	4,875,866		3,239,642
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 10.32
Granted (in dollars per share)	2.08
Exercised (in dollars per share)	2.30
Forfeited (in dollars per share)	9.39
Expired (in dollars per share)	144.59
Outstanding at end of period (in dollars per share)	$ 7.43		$ 10.32
Exercisable (in shares)	1,899,592
Exercisable (in dollars per share)	$ 14.65
Exercisable, Weighted Average Remaining Contractual Term	7 years 6 months
Exercisable, Aggregate Intrinsic Value	$ 450
Vested and Expected to Vest
Outstanding (in shares)	4,875,866
Weighted Average Exercise Price (in dollars per share)	$ 7.43
Weighted-Average Remaining Contractual Term (Years)	8 years 7 months 6 days
Aggregate Intrinsic Value	$ 3,150
Outstanding, weighted average remaining contractual term	8 years 7 months 6 days		8 years 4 months 24 days
Outstanding, Aggregate Intrinsic Value	$ 3,150		$ 8