Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net loss	$ (3,476,144)	$ (1,797,183)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	858,483	616,305
Non-cash equity based compensation	767,840	1,132,064
Gain on sale of long-lived asset	(3,138)	(1,004)
Change in operating assets and liabilities:
Accounts receivable and costs and estimated earnings in excess of billings on uncompleted contracts	(884,010)	(1,100,964)
Inventories	(5,778,912)	(592,822)
Prepaid expenses and other current assets	(784,778)	(257,595)
Accounts payable and other current liabilities	1,340,997	(358,922)
Billings in excess of costs and estimated earnings on uncompleted contracts	38,510	(9,134)
Deferred compensation under executive employment agreements	(665,749)	133,312
Net cash used in operating activities	(8,586,901)	(2,235,943)
Cash flows from investing activities:
Purchases of short-term investments	(7,311,047)	(16,291,905)
Maturities of short-term investments	12,195,677	16,807,566
Decrease (increase) in other long-term assets	(61,828)	1,412
Acquisition of property and equipment	(1,890,405)	(6,069,182)
Property and equipment reimbursements received from DOE under grant	1,325,094	3,004,234
Increase in patent and trademark costs	(18,601)	(7,525)
Cash proceeds from the sale of equipment	3,825	1,004
Net cash used in investing activities	4,242,715	(2,554,396)
Cash flows from financing activities:
Issuance of common stock under employee stock purchase plan	22,994	1,006
Issuance of common stock upon exercise of employee stock options		3,570
Purchase of treasury stock	(12,376)	(143,751)
Net cash provided by (used in) financing activities	10,618	(139,175)
Increase (decrease) in cash and cash equivalents	(4,333,568)	(4,929,514)
Cash and cash equivalents at beginning of period	15,878,752	17,739,600
Cash and cash equivalents at end of period	$ 11,545,184	$ 12,810,086