Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 8,173	$ 21,457
Certificates of deposit	6,000	2,880
Investments held to maturity at amortized cost	8,942	6,077
Accounts receivable, net	54,319	50,338
Income tax receivable	7,316	1,643
Notes receivable	27	28
Inventories, net	68,680	70,786
Prepaid expenses and other	1,230	518
Total current assets	154,687	153,727
Property, plant and equipment:
Land	2,233	2,233
Buildings	94,244	92,075
Machinery and equipment	190,827	184,316
Furniture and fixtures	14,407	13,714
Total property, plant and equipment	301,711	292,338
Less: Accumulated depreciation	153,783	149,963
Property, plant and equipment, net	147,928	142,375
Goodwill	3,677	0
Note receivable	653	678
Total assets	306,945	296,780
Current liabilities:
Revolving credit facility	0	0
Accounts payable	22,214	10,967
Accrued liabilities	35,078	39,098
Total current liabilities	57,292	50,065
Deferred revenue	1,445	1,512
Deferred tax liabilities	8,397	7,977
Donations	200	0
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, 52,394,349 and 52,422,801 issued and outstanding at March 31, 2018 and December 31, 2017, respectively	210	210
Additional paid-in capital	0	0
Retained earnings	239,401	237,016
Total stockholders' equity	239,611	237,226
Total liabilities and stockholders' equity	$ 306,945	$ 296,780

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.