Goodwill and Intangible Assets

The following sets forth the goodwill and intangible assets by major asset class:



		March 31, 2020							December 31, 2019
	Weighted Average Useful Life (Yrs)	Gross		Accumulated Amortization			Net Book Value		Gross		Accumulated Amortization			Net Book Value
Indefinite lived:
Goodwill(a)		$	10,513,371	$	—		$	10,513,371	$	10,513,371	$	—		$	10,513,371
Definite lived:
Licenses	10	1,323,761		(1,255,291		)	68,470		1,323,761		(1,248,104		)	75,657
Bioject(b)	12	5,100,000		(2,248,889		)	2,851,111		5,100,000		(2,175,556		)	2,924,444
Other(c)	18	4,050,000		(3,412,500		)	637,500		4,050,000		(3,356,250		)	693,750
Total intangible assets	11	10,473,761		(6,916,680		)	3,557,081		10,473,761		(6,779,910		)	3,693,851
Total goodwill and intangible assets		$	20,987,132	$	(6,916,680	)	$	14,070,452	$	20,987,132	$	(6,779,910	)	$	14,207,222


(a)	Goodwill was recorded from the Inovio AS acquisition in January 2005, the acquisition of VGX in June 2009 and the acquisition of Bioject in April 2016 for $3.9 million, $6.2 million and $400,000, respectively.


(b)	Bioject intangible assets represent the estimated fair value of developed technology and intellectual property which were recorded from the Bioject asset acquisition.


(c)	Other intangible assets represent the estimated fair value of acquired intellectual property from the Inovio AS acquisition.

Aggregate amortization expense on intangible assets for the three months ended March 31, 2020 and 2019 was $137,000 and $267,000, respectively. Estimated aggregate amortization expense is $410,000 for the remainder of fiscal year 2020, $520,000 for 2021, $493,000 for 2022, $276,000 for 2023, $253,000 for 2024 and $1.6 million for 2025 and subsequent years combined.