Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 31,623	$ 24,153
Certificates of deposit	3,120	5,512
Investments held to maturity at amortized cost	7,139	14,083
Accounts receivable, net	44,377	43,001
Income tax receivable	3,009	6,239
Notes receivable	25	25
Inventories, net	55,988	47,352
Prepaid expenses and other	929	616
Total current assets	146,210	140,981
Property, plant and equipment:
Land	2,233	2,233
Buildings	81,117	78,806
Machinery and equipment	161,024	158,216
Furniture and fixtures	13,315	12,783
Total property, plant and equipment	257,689	252,038
Less: Accumulated depreciation	139,272	137,146
Property, plant and equipment, net	118,417	114,892
Note receivable	656	657
Total assets	265,283	256,530
Current liabilities:
Revolving credit facility	0	0
Accounts payable	9,936	7,102
Accrued liabilities	31,186	31,940
Total current liabilities	41,122	39,042
Deferred revenue	1,546	1,498
Deferred tax liabilities	10,251	9,531
Donations	569	561
Commitments and contingencies
Stockholders' equity:
Preferred stock, $.001 par value, 5,000,000 shares authorized, no shares issued	0	0
Common stock, $.004 par value, 100,000,000 shares authorized, 52,622,539 and 52,651,448 issued and outstanding at March 31, 2017 and December 31, 2016, respectively	210	211
Additional paid-in capital	0	0
Retained earnings	211,585	205,687
Total stockholders' equity	211,795	205,898
Total liabilities and stockholders' equity	$ 265,283	$ 256,530