CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jul. 31, 2021	Apr. 30, 2021
Current assets:
Cash and cash equivalents	$ 159,692	$ 169,915
Accounts receivable	18,354	18,842
Contract assets	5,956	6,112
Inventory	15,242	11,871
Prepaid expenses	1,536	1,064
Total current assets	200,780	207,804
Property and equipment, net	44,569	37,455
Operating lease right-of-use assets	22,877	18,691
Other assets	1,955	1,210
Restricted cash	350	350
Total assets	270,531	265,510
Current liabilities:
Accounts payable	9,611	9,257
Accrued payroll and related costs	4,114	8,794
Contract liabilities	46,262	50,769
Current portion of operating lease liabilities	1,630	1,355
Other current liabilities	1,631	761
Total current liabilities	63,248	70,936
Convertible senior notes, net	138,812	96,949
Operating lease liabilities, less current portion	23,835	19,889
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued and outstanding at July 31, 2021 and April 30, 2021, respectively	0	0
Common stock, $0.001 par value; 150,000 shares authorized; 61,341 and 61,069 shares issued and outstanding at July 31, 2021 and April 30, 2021, respectively	61	61
Additional paid-in capital	597,320	637,534
Accumulated deficit	(552,745)	(559,859)
Total stockholders’ equity	44,636	77,736
Total liabilities and stockholders’ equity	$ 270,531	$ 265,510