CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 6,304	$ 4,730
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	1,009	830
Stock-based compensation	1,299	730
Amortization of debt issuance costs	254	0
Changes in operating assets and liabilities:
Accounts receivable	488	(5,705)
Contract assets	156	(1,017)
Inventory	(3,371)	1,273
Prepaid expenses and other assets	(1,217)	143
Accounts payable	(3,570)	(1,572)
Accrued payroll and related costs	(4,680)	386
Contract liabilities	(4,507)	(1,997)
Other accrued expenses and liabilities	893	(74)
Net cash used in operating activities	(6,942)	(2,273)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(4,199)	(489)
Net cash used in investing activities	(4,199)	(489)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock under equity compensation plans	918	264
Repayment of note payable	0	(4,379)
Dividends paid on preferred stock	0	(1,081)
Principal payments on finance lease	0	(93)
Net cash provided by (used in) financing activities	918	(5,289)
Net decrease in cash, cash equivalents and restricted cash	(10,223)	(8,051)
Cash, cash equivalents and restricted cash, beginning of period	170,265	36,612
Cash, cash equivalents and restricted cash, end of period	160,042	28,561
Supplemental disclosures of non-cash activities:
Unpaid purchases of property and equipment	3,924	1,370
Right-of-use assets obtained upon lease modification, net	$ 4,554	$ 0