|
Goodwill and other intangible assets (Details Textual) (USD $)
|
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2011
|
Jan. 01, 2011
|
|
| Business Acquisition [Line Items] | ||
| Carrying amount of goodwill recorded in conjunction with acquisition of Nekton | $ 7,900,000 | |
| Minimum estimated useful lives for intangible assets | 2 | |
| Maximum estimated useful lives for intangible assets | 10 | |
|
Nekton Research LLC [Member]
|
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| Business Acquisition [Line Items] | ||
| Carrying amount of goodwill recorded in conjunction with acquisition of Nekton | 7,900,000 | |
| Amortization expense related to acquisition of intangible assets | $ 903,000 | $ 475,000 |