Statements Of Cash Flows (USD $)	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
OPERATING ACTIVITIES
Net income	$ 2,566,825	$ 3,377,658
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	190,136	139,271
Deferred income taxes	30,758	3,282
Changes in operating assets and liabilities:
Accounts receivable	51,392	(262,256)
Inventories	104,652	(317,720)
Prepaid expenses and other assets	(101,947)	(39,839)
Accounts payable and accrued expenses	776,867	1,199,601
Net cash provided by operating activities	3,618,683	4,099,997
INVESTING ACTIVITIES
Purchases of fixed assets	0	(445,186)
Purchases of marketable securities	(7,712,423)	(6,195,829)
Proceeds from maturities and sales of marketable securities	3,855,000	2,490,000
Net cash used in investing activities	(3,857,423)	(4,151,015)
Increase in cash and cash equivalents	(238,740)	(51,018)
Cash and cash equivalents at beginning of period	2,509,683	1,544,536
Cash and cash equivalents at end of period	2,270,943	1,493,518
Supplemental disclosures of cash flow information:
Cash paid during the period for income taxes	$ 0	$ 0