CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 42,757	$ 45,160
Short-term investments	125,411	105,105
Accounts receivable, less reserves of $1,100 and $1,131 in 2013 and 2012, respectively	42,780	42,387
Inventories	26,057	26,182
Deferred income taxes	6,325	6,369
Prepaid expenses and other current assets	13,769	14,394
Total current assets	257,099	239,597
Long-term investments	245,484	238,255
Property, plant, and equipment, net	34,647	34,820
Deferred income taxes	17,268	15,647
Intangible assets, net	13,809	14,770
Goodwill	81,689	81,689
Other assets	2,532	2,827
Total assets	652,528	627,605
Current liabilities:
Accounts payable	6,815	6,815
Accrued expenses	24,258	29,590
Accrued income taxes	2,220	1,009
Deferred revenue and customer deposits	13,819	12,690
Total current liabilities	47,112	50,104
Reserve for income taxes	5,955	5,216
Commitments and contingencies (Note 8)
Shareholders' equity:
Common stock, $.002 par value - Authorized: 140,000 shares, issued: 43,452 and 43,055 shares in 2013 and 2012, respectively	87	86
Additional paid-in capital	179,192	165,248
Retained earnings	452,049	436,466
Accumulated other comprehensive loss, net of tax	(31,867)	(29,515)
Total shareholders' equity	599,461	572,285
Total liabilities and shareholders' equity	$ 652,528	$ 627,605