CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net earnings	$ 2,139	$ 3,064	$ 2,070
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	7,892	7,225	7,207
Deferred income taxes	(763)	(338)	(907)
Share-based compensation	939	759	533
Provision for allowances	211	396	1,959
(Gain) loss on marketable securities	(8)	(2)	1
Decommissioning retirement liability	64	58	53
Loss on sale of equipment	10	34	111
Changes in assets and liabilities:
Accounts receivable	2,349	(2,156)	(2,628)
Inventories	516	(2,703)	(1,379)
Refundable income taxes net of income taxes payable	111	(409)	653
Prepaid expenses and other current assets	(29)	(68)	(60)
Other assets	32	(22)	6
Accounts payable	(194)	(28)	(1)
Accrued salaries, wages and payroll taxes	68	521	37
Other current liabilities	(43)	(328)	342
Other	(99)	87	(111)
Net cash provided by operating activities	13,195	6,090	7,886
Cash flows from investing activities:
Purchases and construction of property and equipment	(1,922)	(2,026)	(9,065)
Cash paid for acquisition of Core Oncology customer base	(5,275)
Proceeds from sale of property and equipment		36	7
Purchases of marketable securities	(6,564)	(10,879)	(14,927)
Maturities of marketable securities	5,980	9,575	3,095
Proceeds from sales of marketable securities	785	368	674
Net cash used in investing activities	(6,996)	(2,926)	(20,216)
Cash flows from financing activities:
Cash paid for shares repurchased in tender offer, including transaction costs	(10,382)
Repayment of borrowings	(1,667)	(3,333)	(3,333)
Proceeds from stock purchase plan	72	62	11
Other	(186)	(14)
Net cash used by financing activities	(12,163)	(3,285)	(3,322)
Net decrease in cash and cash equivalents	(5,964)	(121)	(15,652)
Cash and cash equivalents at beginning of year	29,553	29,674	45,326
Cash and cash equivalents at end of year	23,589	29,553	29,674
Supplementary Cash Flow Disclosure
Interest paid	611	806	920
Income taxes paid	1,787	2,650	1,486
Non-cash investing and financing activities:
Liability for property and equipment acquired		32	43
Assets acquired from the Core transaction	$ 48