Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 21,952		$ 12,085
Certificates of deposit	6,098		8,110
Held-to-maturity Securities, Current	11,972		16,040
Accounts receivable, net	44,092		39,063
Income tax receivable	2,569		1,073
Note receivable	30		29
Inventories, net	37,618		32,140
Prepaid expenses and other	609		304
Deferred tax assets	6,143		4,779
Total current assets	131,083		113,623
Property, plant and equipment:
Land	2,233		1,417
Buildings	64,938		61,821
Machinery and equipment	127,968		119,439
Furniture and fixtures	10,388		9,748
Total property, plant and equipment	205,527		192,425
Less: Accumulated depreciation	113,605		105,142
Property, plant and equipment, net	91,922		87,283
Certificates of deposit	5,280		2,638
Held-to-maturity Securities, Noncurrent	4,015		10,981
Note receivable, long-term	817		919
Total assets	233,117		215,444
Current liabilities:
Revolving credit facility	0		0
Accounts payable	11,370		7,779
Accrued liabilities	31,343		28,550
Total current liabilities	42,713		36,329
Deferred revenue	1,006		585
Deferred tax liabilities	13,677		14,424
Donations	1,662		0
Commitments and contingencies
Stockholders' equity:
Preferred stock, $.001 par value, 5,000,000 shares authorized, no shares issued
Common stock, $.004 par value, 100,000,000 shares authorized, 54,041,829 and 55,067,031 issued and outstanding at December 31, 2014 and 2013, respectively	216	[1]	221	[1]
Additional paid-in capital	0		0
Retained earnings	173,843		163,885
Total stockholders' equity	174,059		164,106
Total liabilities and stockholders' equity	$ 233,117		$ 215,444

[1] Reflects three-for-two stock split effective July 16, 2014