Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2024	Jan. 31, 2023
Operating expenses:
Research and development	$ 22,523	$ 20,063	$ 60,919	$ 56,325
General and administrative	10,628	6,882	31,071	22,818
Total operating expenses	33,151	26,945	91,990	79,143
Operating loss	(33,151)	(26,945)	(91,990)	(79,143)
Other income:
Interest income	684	732	2,383	1,424
Foreign currency exchange gain (loss)	1,120	597	277	(237)
Other income	2,319	4,313	7,335	11,354
Total other income	4,123	5,642	9,995	12,541
Net loss	(29,028)	(21,303)	(81,995)	(66,602)
Other comprehensive (loss) income:
Foreign currency translation (loss) gain	(46)	1,128	(373)	(573)
Unrealized holding gain on marketable securities	438	658	1,270	808
Reclassification adjustment for realized (gain) loss on marketable securities included in net loss	(221)	(1)	(1,130)	84
Other comprehensive gain (loss)	171	1,785	(233)	319
Comprehensive loss	$ (28,857)	$ (19,518)	$ (82,228)	$ (66,283)
Net loss per share to common stockholders, basic	$ (0.84)	$ (0.75)	$ (2.37)	$ (2.58)
Net loss per share to common stockholders, diluted	$ (0.84)	$ (0.75)	$ (2.37)	$ (2.58)
Weighted average common shares outstanding, basic	34,723,379	28,278,453	34,567,853	25,810,369
Weighted average common shares outstanding, diluted	34,723,379	28,278,453	34,567,853	25,810,369