Changes in the carrying amount of goodwill for the nine months ended September 30, 2021 were as follows:


	Total



Goodwill at January 1, 2021	$	70,511



Foreign currency translation impact	(21)
Goodwill at September 30, 2021	$	70,490

As of September 30, 2021, the balances of amortizable intangible assets were as follows:


	Weighted-Average Amortization Period	Gross Intangible Assets		Accumulated Amortization		Net Intangible Assets
Patents	14.0 years	$	43,349	$	(4,807)	$	38,542
Intellectual Property	9.6 years	8,990		(1,232)		7,758
License Agreements	5.9 years	10,674		(2,070)		8,604
Total amortizable assets		$	63,013	$	(8,109)	$	54,904

As of December 31, 2020, the balances of amortizable intangible assets were as follows:


	Weighted-Average Amortization Period	Gross Intangible Assets		Accumulated Amortization		Net Intangible Assets
Patents	14.7 years	$	43,363	$	(2,650)	$	40,713
Intellectual Property	10.3 years	8,990		(744)		8,246
License Agreements	2.7 years	2,765		(1,440)		1,325
Total amortizable assets		$	55,118	$	(4,834)	$	50,284

On September 3, 2021, we entered into a five-year license agreement, resulting in exclusive distribution rights of the 7D Surgical FLASHTM Navigation platform for pediatric applications. We paid $750 which will be amortized over the initial three years of the agreement.

On July 20, 2021, we entered into an amended license agreement, resulting in a five-year extension of our exclusive distribution rights of the FIREFLY Technology in children's hospitals across the United States. We paid $4,300 for the amended agreement and the amount will be amortized over the life of the agreement.

On March 19, 2021, we recorded a license agreement in the amount of $2,858 in settlement of the Barry legal matter. Amortization is recorded based on the cases completed in the given period.

On June 10, 2020, we purchased certain intellectual property assets from Band-Lok, LLC, a North Carolina limited liability company ("Band-Lok"), related to its Tether Clamp and Implantation System ("Tether Clamp System") for $3,394 in total consideration. We use the Tether Clamp System in connection with our Bandloc 5.5/6.0 System. We were previously the sole licensee of the purchased assets under a license agreement with Band-Lok.

Licenses are tied to product launches and do not begin amortizing until the product is launched to the market.