Intangible Assets

12 Months Ended

Mar. 31, 2013

Intangible Assets

Intangible Assets

5. Intangible Assets

        Intangible assets consisted of the following (in thousands):

	March 31, 2013
	Weighted Average Amortization Period	Intangible Assets, Gross		Accumulated Amortization		Intangible Assets, Net
Manufacturing license	17 years	$	3,700	$	3,487	$	213
Technology	10 years		2,240		709		1,531
Parts and service customer relationships	5 years		1,080		684		396
TA100 customer relationships	2 years		617		617		—
Backlog	Various		490		317		173
Trade name	1.2 years		69		69		—
Total		$	8,196	$	5,883	$	2,313

	March 31, 2012
	Weighted Average Amortization Period	Intangible Assets, Gross		Accumulated Amortization		Intangible Assets, Net
Manufacturing license	17 years	$	3,700	$	3,437	$	263
Technology	10 years		2,240		485		1,755
Parts and service customer relationships	5 years		1,080		468		612
TA100 customer relationships	2 years		617		617		—
Backlog	Various		490		309		181
Trade name	1.2 years		69		69		—
Total		$	8,196	$	5,385	$	2,811

        Amortization expense for the intangible assets was $0.5 million, $0.8 million, and $1.1 million for the years ended March 31, 2013, 2012 and 2011.

        Expected future amortization expense of intangible assets as of March 31, 2013 is as follows (in thousands):

Year Ending March 31,	Amortization Expense
2014	$	582
2015		532
2016		273
2017		273
2018		242
Thereafter		411
Total expected future amortization	$	2,313

        The manufacturing license provides the Company with the ability to manufacture recuperator cores previously purchased from Solar Turbines Incorporated ("Solar"). The Company is required to pay a per-unit royalty fee over a seventeen-year period for cores manufactured and sold by the Company using the technology. Royalties of approximately $76,700, $72,800, and $62,800 were earned by Solar for the years ended March 31, 2013, 2012 and 2011, respectively. Earned royalties of approximately $24,600 and $17,500 were unpaid as of March 31, 2013 and 2012, respectively, and are included in accrued expenses in the accompanying balance sheets.