Intangible Assets

The following table sets forth the carrying value of intangible assets by reporting segment:



(in thousands)	As of September 30, 2013							As of September 30, 2012
	Gross Assets		Accumulated Amortization			Net Assets		Gross Assets		Accumulated Amortization			Net Assets
Fiber Optics:
Core Technology	$	12,727	$	(11,822	)	$	905	$	12,727	$	(11,150	)	$	1,577
Customer Relations	3,511		(2,647		)	864		3,511		(2,359		)	1,152
Patents	4,697		(4,498		)	199		4,697		(4,381		)	316
	20,935		(18,967		)	1,968		20,935		(17,890		)	3,045
Photovoltaics:
Patents	1,972		(1,781		)	191		1,972		(1,589		)	383
Total	$	22,907	$	(20,748	)	$	2,159	$	22,907	$	(19,479	)	$	3,428

In May 2012, we sold approximately $0.5 million of fiber optics-related intangible assets, net of accumulated amortization, to SEI pursuant to a Master Purchase Agreement signed in March 2012. See Note 1 - Description of Business for additional disclosures related to this asset sale.

Amortization expense related to intangible assets is included in sales, general, and administrative expense on our statement of operations and comprehensive income (loss). Based on the carrying amount of our intangible assets as of September 30, 2013, the estimated future amortization expense is as follows:



Estimated Future Amortization Expense
(in thousands)
Fiscal year ended September 30, 2014	$	1,017
Fiscal year ended September 30, 2015	555
Fiscal year ended September 30, 2016	554
Fiscal year ended September 30, 2017	33
Fiscal year ended September 30, 2018 and thereafter	—
Total	$	2,159

Impairment Testing

The impairment tests for our long-lived assets involves comparing fair value to the carrying amount. If the carrying value of the long-lived assets (asset group) exceeds the estimated undiscounted cash flows expected to be generated by the assets, an impairment may exist. We derive fair value using both the guideline public company valuation method, and on a lesser extent, the discounted cash flow valuation method. The guideline public company valuation method entails a comparison to publicly traded companies within similar industry, product lines, market, growth, margins and risk and is generally based on published data regarding the public companies' stock price, revenue, and earnings. The discounted cash flow valuation method is based on both undiscounted and discounted cash flow models using assumptions about revenue growth rates, appropriate discount rates relative to risk, and estimates of terminal value.

Fiscal 2011:

As of September 30, 2011, we performed an impairment test of long-lived assets associated with our digital fiber optics product lines. The impairment test was triggered by a change in long-term financial and cash flow forecasts. The changes in financial and cash forecasts as of September 30, 2011 were not a result of the flooding in Thailand. The financial impact from this natural disaster was considered a fiscal 2012 first quarter event. As a result of our evaluation we determined that impairment existed and a charge of 8.0 million was recorded to write down long-lived assets. Of the total impairment charge, $5.3 million related to fixed assets and $2.7 million related to intangible assets. As of September 30, 2011, long-lived assets associated with our digital fiber optics product lines totaled $17.1 million.

Fiscal 2012:

As of December 31, 2011, we performed an impairment test of long-lived assets within our Fiber Optics segment and we determined that no impairment existed. The impairment test was triggered by a change in long-term financial and cash flow forecasts due to the adverse impact the Thailand flood had on our operations. See Note 11 - Impact from Thailand Flood for additional disclosures related to the impact of the Thailand flood on our operations. In making this determination, we used certain assumptions, including estimates of future cash flows expected to be generated by these long-lived assets, which are based on additional assumptions such as asset utilization, expected length of service from the assets, and estimated salvage values. If we are unable to achieve projected cash flows, we may be required to perform additional impairment tests of our remaining long-lived assets which may result in the recording of impairment charges.

As of June 30, 2012, we performed an evaluation of an asset group within our Photovoltaics segment for impairment of long-lived assets. The impairment test was triggered by a determination that it was more likely than not those assets would be sold or otherwise disposed of before the end of their previously estimated useful lives. As a result of the evaluation, we determined that impairment existed and a charge of $1.4 million was recorded to write down the long-lived assets to an estimated fair value. Of the total impairment charge, $1.1 million related to equipment and $0.3 million related to intangible assets.

Fiscal 2013

As of September 30, 2013, we performed an impairment test on certain long-lived assets related to our Fiber Optics segment. The impairment test was triggered by a change in long-term financial and cash flow forecasts. The impairment testing indicated that no impairment existed and that future undiscounted cash flows exceeded the carrying value.