INTANGIBLE ASSETS

As of the dates indicated, intangible assets are comprised of the following (in thousands):



	October 31,
	2018							2017
	Gross Intangible		Accumulated Amortization			Net Intangible		Gross Intangible		Accumulated Amortization			Net Intangible
Developed technology	$	373,581	$	(285,233	)	$	88,348	$	341,255	$	(266,693	)	$	74,562
In-process research and development	—		—			—		671		—			671
Patents and licenses	3,565		(1,958		)	1,607		7,165		(6,535		)	630
Customer relationships, covenants not to compete, outstanding purchase orders and contracts	374,620		(316,350		)	58,270		334,642		(309,508		)	25,134
Total intangible assets	$	751,766	$	(603,541	)	$	148,225	$	683,733	$	(582,736	)	$	100,997

During fiscal 2018 and 2017, certain fully amortized intangible assets of approximately $5.0 million and $34.0 million, respectively, were eliminated from gross intangible assets and accumulated amortization during the period, with no corresponding impact to the income statement. These assets were primarily technology for products no longer being sold by Ciena.

The aggregate amortization expense of intangible assets was $25.8 million, $45.7 million and $78.3 million for fiscal 2018, fiscal 2017 and fiscal 2016, respectively. Expected future amortization of intangible assets for the fiscal years indicated is as follows (in thousands):



Year Ended October 31,
2019	$	35,375
2020	34,019
2021	30,841
2022	24,820
2023	10,011
Thereafter	13,159
	$	148,225