Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable intangible assets acquired in a business combination. In connection with the May 2019 announcement for the divestiture of the Wi-Fi business, the Company reclassified $557.8 million of goodwill to assets held for sale. See “Note 4 - Business Combination” for discussion of the Cavium acquisition and "Note 1 - Basis of Presentation" for discussion of the Wi-Fi divestiture.

As of August 3, 2019 and February 2, 2019, net carrying amounts of acquired intangible assets are as follows (in thousands, except for weighted average remaining amortization period):



	August 3, 2019
	Gross Carrying Amounts		Accumulated Amortization			Net Carrying Amounts		Weighted average remaining amortization period (years)
Developed technologies	$	1,868,000	$	(255,206	)	$	1,612,794	6.75
Customer contracts and related relationships	465,000		(82,850		)	382,150		7.92
Trade names	23,000		(5,969		)	17,031		3.40
Total acquired amortizable intangible assets	$	2,356,000	$	(344,025	)	$	2,011,975	6.95
IPR&D	388,000		—			388,000		n/a
Total acquired intangible assets	$	2,744,000	$	(344,025	)	$	2,399,975



	February 2, 2019
	Gross Carrying Amounts		Accumulated Amortization			Net Carrying Amounts		Weighted average remaining amortization period (years)
Developed technologies	$	1,743,000	$	(134,167	)	$	1,608,833	7.10
Customer contracts and related relationships	465,000		(45,939		)	419,061		8.42
Trade names	23,000		(3,212		)	19,788		3.85
Total acquired amortizable intangible assets	$	2,231,000	$	(183,318	)	$	2,047,682	7.34
IPR&D	513,000		—			513,000		n/a
Total acquired intangible assets	$	2,744,000	$	(183,318	)	$	2,560,682

The intangible assets are amortized on a straight-line basis over the estimated useful lives, except for customer contracts and related relationships, which are amortized using an accelerated method of amortization over the expected customer lives, which more accurately reflects the pattern of realization of economic benefits expected to be obtained. The IPR&D will be accounted for as an indefinite-lived intangible asset and will not be amortized until the underlying projects reach technological feasibility and commercial production at which point the IPR&D will be amortized over the estimated useful life. Useful lives for these IPR&D projects are expected to range between 4 to 9 years. In the event the IPR&D is abandoned the related assets will be written off.

Amortization expense for acquired intangible assets for the three and six months ended August 3, 2019 was $81.0 million and $160.7 million, respectively. Amortization expense for acquired intangible assets for the three and six months ended August 4, 2018 was $25.9 million.