7.  Intangible Assets

 

The Company recorded amortization expense of $0.1 million and $0.2 million for the three and nine months ended December 31, 2015, respectively. The Company recorded amortization expense of $0.1 million and $0.4 million for the three and nine months ended December 31, 2014, respectively. Intangible assets consisted of the following (in thousands):

 

 

 

Expected future amortization expense of intangible assets as of December 31, 2015 is as follows (in thousands):

 

 

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 $7,200 and $18,100 were earned by Solar for the three months ended December 31, 2015 and 2014, respectively. Royalties of approximately $26,400 and $51,800 were earned by Solar for the nine months ended December 31, 2015 and 2014, respectively. Earned royalties of approximately $26,400 and $19,300 were unpaid as of December 31, 2015 and March 31, 2015, respectively, and are included in accounts payable and accrued expenses in the accompanying balance sheets.