CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	6 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 549,077	$ 1,611,262
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	812,208	809,236
Stock-based compensation expense	526,614	505,012
Changes in assets and liabilities:
Accounts receivable	(2,760,868)	(1,525,973)
Royalties receivable	(276,856)	(217,000)
Inventories	(506,109)	164,277
Prepaid expenses and other current assets	(432,574)	261,043
Accounts payable	(350,154)	(92,375)
Accrued liabilities	(120,006)	(819,457)
Long-term liabilities	(3,836)	(22,298)
Net cash (used in) provided by operating activities	(2,562,504)	673,727
Cash flows from investing activities:
Purchases of marketable securities	(39,147,022)	(33,407,486)
Redemptions of marketable securities	38,675,570	35,500,000
Purchases of property, plant and equipment	(338,634)	(154,749)
Net cash (used in) provided by investing activities	(810,086)	1,937,765
Cash flows from financing activities:
Exercise of stock options	25	25,758
Repurchase of common stock	(330,867)
Net cash (used in) provided by financing activities	(330,842)	25,758
Net (decrease) increase in cash and cash equivalents	(3,703,432)	2,637,250
Cash and cash equivalents, beginning of period	14,203,544	12,526,040
Cash and cash equivalents, end of period	$ 10,500,112	$ 15,163,290

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Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits are not generally reported as cash and cash equivalents. Includes cash and cash equivalents associated with the entity's continuing operations. Excludes cash and cash equivalents associated with the disposal group (and discontinued operation).