5. Benefit Plans (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Cash received from stock options exercised	$ 1,278	$ 752	$ 31
Company matching contributions to 401(k) plan	$ 377	$ 564	$ 845
Employee Stock Purchase Plan [Member]
Weighted average grant date fair value, other than options	$ 1.49	$ 1.65	$ 1.07
Stock issued during period, ESPP	75,148	88,327	270,075
ESPO weighted average purchase price	$ 3.44	$ 3.59	$ 1.95
Stock Option [Member]
Weighted-average grant date fair value of options granted	$ 3.30	$ 3.50	$ 2.86
Aggregate intrinsic value of stock options exercised	$ 547	$ 173	$ 11
Cash received from stock options exercised	1,278	$ 752	$ 31
Unrecognized compensation costs related to non-vested stock options	$ 3,880
Unrecognized compensation cost weighted average vesting period	2 years 8 months 12 days
RSUs [Member]
Unrecognized compensation cost weighted average vesting period	3 years 4 months 2 days
RSU's granted during period	0
Unrecognized compensation cost related to non-vested RSUs	$ 733
Stock Incentive Plans [Member]
Stock reserved for issuance	7,246,713
Stock Incentive Plans [Member] \| Options and RSU's [Member]
Stock reserved for issuance	3,474,590
Stock Incentive Plans [Member] \| Future Grants [Member]
Stock reserved for issuance	3,790,123
Employee Stock Purchase Plan [Member]
Stock reserved for issuance	1,196,261

Aggregate number of common shares reserved for future issuance.

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