CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Apr. 30, 2019	Apr. 30, 2018
CURRENT ASSETS:
Cash and cash equivalents	$ 32,351	$ 42,265
Accounts receivable	7,374	3,754
Contract assets	4,327	0
Inventories	6,557	16,129
Prepaid expenses	709	679
Assets of discontinued operations	0	5,000
Total current assets	51,318	67,827
Property and equipment, net	25,625	26,479
Restricted cash	1,150	1,150
Other assets	302	304
TOTAL ASSETS	78,395	95,760
CURRENT LIABILITIES:
Accounts payable	4,352	1,909
Accrued payroll and related costs	3,540	2,564
Contract liabilities	14,651	27,935
Other current liabilities	619	905
Liabilities of discontinued operations	0	4,550
Total current liabilities	23,162	37,863
Deferred rent, less current portion	2,072	2,159
Capital lease, less current portion	93	0
Commitments and contingencies (Note 8)
STOCKHOLDERS' EQUITY:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; 1,647,760 shares issued and outstanding at respective dates	2	2
Common stock, $0.001 par value; 150,000,000 shares authorized; 56,135,697 and 55,689,222 shares issued and outstanding at respective dates	56	55
Additional paid-in-capital	613,615	614,810
Accumulated deficit	(560,605)	(559,129)
Total stockholders' equity	53,068	55,738
Total liabilities and stockholders' equity	$ 78,395	$ 95,760