As of March 31, 2022 and December 31, 2021, the short-term restricted cash balance was $0.5 million, which was comprised of security deposits for the credit cards of employees.

As of March 31, 2022 and December 31, 2021, our inventory, net, consisted of the following components:

For our facility located at 1305 O’Brien Drive, Menlo Park, California (the “O’Brien Lease”), we were required to establish a letter of credit for the benefit of the landlord and to submit $4.5 million as a deposit for the letter of credit in October 2015. Subsequently, pursuant to the terms of the O’Brien Lease, beginning on May 1, 2019, the amount of the letter of credit was reduced by $0.5 million each year thereafter on May 1. As such, $3.0 million was recorded in long-term restricted cash related to the O’Brien Lease in the Condensed Consolidated Balance Sheets as of March 31, 2022 and December 31, 2021, respectively. In connection with the acquisition of Omniome in September 2021, we acquired $1.6 million of long-term restricted cash related to a letter of credit established for a facility lease. At March 31, 2022, we had an additional $0.4 million in long-term restricted cash primarily related to lease deposits.

Intangible Assets and Goodwill

Intangible assets include acquired in-process research and development (IPR&D) of $400 million as a result of the Omniome acquisition in September 2021. The IPR&D will remain on our consolidated balance sheet as an indefinite-lived intangible asset until the completion or abandonment of the associated research and development activities. During the development period following the acquisition, IPR&D will not be amortized, but instead will be tested for impairment annually and more frequently if events or changes in circumstances indicate that it is more likely than not that the asset is impaired. Upon completion of the development, we will begin to amortize the asset over the life of the product, or record an impairment charge if the asset is determined to be impaired.

In addition to IPR&D, we had the following definite-lived intangible assets from business acquisitions (in thousands, except years):


		As of March 31, 2022						As of December 31, 2021
	Estimated	Gross				Net		Gross				Net
	Useful Life	Carrying		Accumulated		Carrying		Carrying		Accumulated		Carrying
	(in years)	Amount		Amortization		Amount		Amount		Amortization		Amount
Developed technology	15	$	11,000	$	(489)	$	10,511	$	11,000	$	(306)	$	10,694
Customer relationships	2		360		(120)		240		360		(75)		285
Total		$	11,360	$	(609)	$	10,751	$	11,360	$	(381)	$	10,979

The estimated future amortization expense of acquisition-related intangible assets with definite lives is estimated as follows:


		(in thousands)
Remainder of 2022	$	685
2023		838
2024		733
2025		733
2026		733
2027 and thereafter		7,029
Total	$	10,751

We review definite-lived intangible assets for impairment when indication of potential impairment exists, such as a significant reduction in cash flows associated with the assets.

Goodwill is reviewed for impairment at least annually during the second quarter, or more frequently if an event occurs indicating the potential for impairment. We had no indicators of impairment related to goodwill during the three months ended March 31, 2022.

Deferred revenue

As of March 31, 2022, we had a total of $38.0 million of deferred revenue, $12.7 million of which was recorded as deferred revenue, current and primarily relates to deferred service contract revenues to be recognized over the next year and the remaining $25.2 million was recorded as deferred revenue, non-current. Of the deferred revenue, non-current balance, $23.5 million relates to payments received under the Invitae collaboration described in Note 3. Invitae Collaboration in Part I, Item 1 of this Quarterly Report on Form 10-Q and $1.7 million primarily relates to deferred service contract revenues and is scheduled to be recognized in the next 5 years. Revenue recorded in the three months ended March 31, 2022 includes $4.0 million of previously deferred revenue that was included in deferred

revenue, current as of December 31, 2021. Contract assets as of March 31, 2022 and December 31, 2021 were not material.

As of March 31, 2022, we had a total of $0.6 million of deferred commissions included in prepaid expenses and other current assets which is recognized as sales, general and administrative expense as the related revenue is recognized. Costs to obtain a contract are expensed as incurred if the amortization period would have been a year or less.

In connection with the acquisition of Omniome, we acquired $1.3 million in short-term debt and $3.0 million in long-term debt relating to a term loan facility that Omniome obtained in April 2020. Borrowings on the term loan facility were used to fund Omniome’s purchases of equipment, which serves as collateral. Each term loan has a term of 43 months and bears a fixed interest rate of approximately 17% annually. The fee for the elective option to prepay all, but not less than all, of the borrowed amounts at any time after the 24^th month and before the 43^rd month after the commencement date, is 4% of the outstanding loan balance. Payments are made in equal monthly installments including principal and interest. The following table presents the future principal payments on the term loans: