CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jan. 31, 2019	Apr. 30, 2018
Current assets:
Cash and cash equivalents	$ 27,758	$ 42,265
Trade and other receivables	7,885	3,754
Contract assets	3,912	0
Inventories	8,660	16,129
Prepaid expenses	567	679
Assets of discontinued operations	0	5,000
Total current assets	48,782	67,827
Property and equipment, net	25,876	26,479
Restricted cash	1,150	1,150
Other assets	302	304
Total assets	76,110	95,760
Current liabilities:
Accounts payable	2,916	1,909
Accrued payroll and related costs	2,549	2,564
Contract liabilities	14,620	27,935
Other current liabilities	638	905
Liabilities of discontinued operations	125	4,550
Total current liabilities	20,848	37,863
Deferred rent, less current portion	2,105	2,159
Capital lease, less current portion	93	0
Commitments and contingencies
STOCKHOLDERS' EQUITY:
Preferred stock $0.001 par value; 5,000,000 shares authorized; 1,647,760 shares issued and outstanding at January 31, 2019 and April 30, 2018, respectively	2	2
Common stock $0.001 par value; 150,000,000 shares authorized; 56,072,291 and 55,689,222 shares issued and outstanding at January 31, 2019 and April 30, 2018, respectively	56	55
Additional paid-in-capital	613,947	614,810
Accumulated deficit	(560,941)	(559,129)
Total stockholders' equity	53,064	55,738
Total liabilities and stockholders' equity	$ 76,110	$ 95,760