5.	Intangible Assets

The reconciliation of intangible assets for the nine months ended March 31, 2018 and for the year ended June 30, 2017 was as follows (in thousands):


	Nine Months Ended March 31, 2018			Year Ended June 30, 2017
Patented technologies
Gross carrying amount at beginning of period	$	35,610		$	36,196
Acquisition of Icon Bioscience		31,973			—
Foreign currency translation adjustments		739			(586	)

Gross carrying amount at end of period		68,322			35,610

Accumulated amortization at beginning of period		(35,246	)		(35,094	)
Amortization expense		(366	)		(724	)
Foreign currency translation adjustments		(737	)		572

Accumulated amortization at end of period		(36,349	)		(35,246	)

Net book value at end of period	$	31,973		$	364

The Company historically amortized its intangible assets with finite lives on a straight-line basis over their respective estimated useful lives. Amortization of intangible assets totaled $0 and $180,000 for the three months ended March 31, 2018 and 2017, respectively, and $366,000 and $542,000 for the nine months ended March 31, 2018 and 2017, respectively. At March 31, 2018, the carrying value of each of the Durasert and Tethadur intangible assets was amortized to zero.

In connection with the Icon Acquisition (see Note 3), the initial purchase price of $32.0 million was attributed to the DEXYCU product intangible asset. This finite-lived intangible asset will be amortized proportionate to projected DEXYCU product revenues over its expected useful life. No amortization expense was recorded related to DEXYCU for the three months ended March 31, 2018 and no amortization is expected for the remainder of fiscal year 2018 or until such time as the commercial sales of the product are commenced.