		2019				2018
	Weighted Average Life	Gross Amount		Accumulated Amortization		Gross Amount		Accumulated Amortization
Intangibles:
Patents and licenses, software and hardware designs	6 years	$	3,432	$	1,731	$	5,177	$	3,430
Developed technology	10 years		2,782		2,782		2,782		2,573
Customer relationships and non-compete	9 years		—		—		2,838		2,838
		$	6,214	$	4,513	$	10,797	$	8,841

Amortization expense for 2019 and 2018 was $720 and $889, respectively. Estimated amortization expense for each of the ensuing years through December 31, 2024 is $490, $472, $189, $148 and $31, respectively.

	2019		2018
Other assets:
Inventories - bauxite raw materials	$	4,012	$	4,160
Investment in PicOnyx		128		—
PicOnyx promissory note		500		—
Other		784		1,034
	$	5,424	$	5,194

Bauxite raw materials are used in the production of heavyweight ceramic products. As of December 31, 2019, and 2018, the Company has classified as long-term assets those bauxite raw materials inventories that are not expected to be consumed in production during the upcoming twelve-month period.

On May 28, 2019, the Company entered into an agreement with PicOnyx, Inc. (“PicOnyx”) pursuant to which the Company agreed to provide certain services and contribute certain manufacturing assets to PicOnyx in exchange for 9.7 million shares of convertible preferred stock in PicOnyx. At the Company’s election, the preferred stock can be converted into a pre-determined number of shares of common stock. Additionally, the preferred stock has voting rights that give the Company approximately 22% of voting rights based on the number of outstanding shares of PicOnyx stock. As part of its agreement with PicOnyx, the Company is also designated a seat on the PicOnyx Board of Directors. The Company also holds a warrant to purchase additional shares from PicOnyx with a nominal exercise price in the event of certain qualified financings. In addition, the Company entered into a Contract Manufacturing Services Agreement with PicOynx, pursuant to which the Company agreed to provide contract manufacturing services to PicOnyx for certain of its products. Pursuant to the terms of the Subscription and Asset Contribution Agreement, the Company has agreed to lease certain property to PicOnyx. During the second quarter of 2019, the Company initially recorded its investment in PicOnyx at the fair value of the assets given up, which at the time approximated the book value and which the Company believes represents the standalone selling price. The fair value was estimated using equipment appraisals (Level 3 inputs as defined in ASC 820). No gain or loss was recorded at inception of the investment. Given that the Company’s investment in PicOnyx does not have a readily-determinable fair value, the Company measures the investment at cost, less any impairment, and will adjust the investment to fair value to the extent an observable price change for identical or similar investments of PicOnyx is identified. The transaction resulted in a non-cash change in Property, plant and equipment and Intangible and other assets, net of approximately $3,500 as well as a non-cash change in Accounts Payable and Intangible and other assets, net of approximately $400. PicOnyx represents a variable interest entity for which the Company holds a variable interest. The Company does not consolidate PicOnyx as the Company is not the primary beneficiary because the Company does not have the power to direct the activities that most significantly impact PicOnyx’s economic performance. PicOnyx plans to sell M-Tone, an innovative family of unique, high performance black pigments which addresses customer needs for black pigments with higher performance and greater functionality that are more environmentally friendly than other available alternatives. During the fourth quarter of 2019, as a result of delays in the commercialization of its product and insufficient liquidity being available for PicOnyx to meet its operating objectives, the Company identified indicators of impairment relating to its investment in PicOnyx. As such, the Company recorded an impairment of $4,130 within other operating expense. After impairment, the fair value of the Company’s investment in PicOnyx is approximately $128 at December 31, 2019 based on Level 3 inputs, representing the Company’s maximum exposure to loss, and is recorded in Intangible and other assets, net on the consolidated balance sheet. In addition, the Company provided PicOnyx $500 in exchange for a convertible promissory note. The note will automatically be converted to equity shares if certain qualified financings occur. The convertible promissory note bears interest at 7.5% per year. The note matures on the earlier of August 1, 2021 or the termination of the Contract Manufacturing Services Agreement. The note is collateralized by all of the manufacturing assets the Company contributed to PicOnyx and is recorded within Intangible and other assets, net on the consolidated balance sheet at December 31, 2019.

For additional information, refer to Note 5 – Other Operating Expense (Income).