Major Customers (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenue, Major Customer [Line Items]
Total product sales	$ 32,146,000	$ 41,209,000	$ 65,004,000	$ 85,540,000
Total tooling sales	2,535,000	3,335,000	4,039,000	3,533,000
Total sales	34,681,000	44,544,000	69,043,000	89,073,000
Navistar [Member]
Revenue, Major Customer [Line Items]
Total sales	12,540,000	16,018,000	24,807,000	32,892,000
Paccar [Member]
Revenue, Major Customer [Line Items]
Total sales	12,590,000	15,278,000	24,061,000	31,811,000
Yamaha [Member]
Revenue, Major Customer [Line Items]
Total sales	2,907,000	3,743,000	6,914,000	7,946,000
Other Customers [Member]
Revenue, Major Customer [Line Items]
Total sales	6,644,000	9,505,000	13,261,000	16,424,000
Product Sales [Member] \| Navistar [Member]
Revenue, Major Customer [Line Items]
Total sales	11,980,000	15,055,000	24,218,000	31,854,000
Product Sales [Member] \| Paccar [Member]
Revenue, Major Customer [Line Items]
Total sales	11,030,000	15,082,000	21,852,000	31,521,000
Product Sales [Member] \| Yamaha [Member]
Revenue, Major Customer [Line Items]
Total sales	2,907,000	3,743,000	6,914,000	7,942,000
Product Sales [Member] \| Other Customers [Member]
Revenue, Major Customer [Line Items]
Total sales	6,229,000	7,329,000	12,020,000	14,223,000
Tooling Sales [Member] \| Navistar [Member]
Revenue, Major Customer [Line Items]
Total sales	560,000	963,000	589,000	1,038,000
Tooling Sales [Member] \| Paccar [Member]
Revenue, Major Customer [Line Items]
Total sales	1,560,000	196,000	2,209,000	290,000
Tooling Sales [Member] \| Yamaha [Member]
Revenue, Major Customer [Line Items]
Total sales	0	0	0	4,000
Tooling Sales [Member] \| Other Customers [Member]
Revenue, Major Customer [Line Items]
Total sales	$ 415,000	$ 2,176,000	$ 1,241,000	$ 2,201,000

Revenue earned during the period arising from products sold or services provided under the terms of a contract, not elsewhere specified in the taxonomy. May include government contracts, construction contracts, and any other contract related to a particular project or product.

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- Details

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Balance Type:	na
Period Type:	duration

- Definition

Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
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