Intangible assets
 12 Months Ended
Dec. 31, 2013
Intangible Assets, Net (Excluding Goodwill) [Abstract]  
Intangible assets
Intangible assets
Intangible assets and accumulated amortization balances at December 31, 2012 and December 31, 2013, are as follows:
(dollars in thousands)
December 31,
2012
 
December 31,
2013
Trade name
$
13

 
$
13

Licenses and patents
4,284

 
4,578

Non-competition agreements
571

 
641

 
4,868

 
5,232

Less accumulated amortization:
 
 
 
Trade name
(13
)
 
(13
)
Licenses and patents
(434
)
 
(746
)
Non-competition agreements
(226
)
 
(351
)
 
(673
)
 
(1,110
)
Total, net
$
4,195

 
$
4,122


As of December 31, 2012 and 2013, the trade name was fully amortized. The remaining weighted-average useful lives of the other intangible assets as of December 31, 2013 are as follows:
Licenses and patents
12.3 years
Non-competition agreements
2.1 years
Total intangible assets
11.6 years


In June 2012, the Company paid $210,000 to, and terminated certain licenses with, Wisconsin Alumni Research Foundation in exchange for a new license encompassing many, but not all, of the previously licensed patents as well as some additional patents. The net book value of the exchanged licenses was added to the cash payment to determine the value of the new license.
The future amortization of intangible assets recorded as of December 31, 2013 is as follows:
(Dollars in thousands)
 
Years ending December 31,
Amount
2014
$
556

2015
521

2016
372

2017
358

2018
323

Thereafter
1,992

 
$
4,122



Amortization expense was $257,000, $347,000 and $522,000 for 2011, 2012 and 2013, respectively.
A portion of the July 30, 2013 stock option grants to a scientific founder of the Company were issued in exchange for extending the non-competition agreement from December of 2015 to July of 2016. As of the grant date, the Company increased the value of the non-competition agreement by $70,000 and began amortizing that amount through July of 2016.