6. Goodwill and Other Intangible Assets

Goodwill — Goodwill represents the excess of the purchase price over the identifiable tangible and intangible assets acquired plus liabilities assumed arising from business combinations. The balance of goodwill was $1.9 million as of June 30, 2025 and December 31, 2024 as a result of the Company's acquisition of V-Go in May 2022. Goodwill is tested at least annually for impairment by assessing qualitative factors in determining whether it is more likely than not that the fair value of net assets is below their carrying amounts. See Note 1 – Description of Business and Significant Accounting Policies.

Amortization expense related to the developed technology was de minimis for the three and six months ended June 30, 2025 and 2024. The estimated annual amortization expense for the developed technology will be approximately $0.2 million per year for the years ended December 31, 2025 through 2029.

The iSPERSE License — IPR&D is an indefinite-lived intangible asset which is tested for impairment when facts or circumstances indicate the carrying value of the asset may not be recoverable. Upon completion of the underlying R&D efforts, the intangible asset will be accounted for as a finite-lived intangible asset. If the R&D efforts are abandoned, the IPR&D asset balance will be written off to R&D expense. The iSPERSE License – IPR&D was acquired from Pulmatrix, Inc. ("Pulmatrix") in July 2024.

The Company evaluates its other intangible assets for potential impairment when events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. See Note 1 – Description of Business and Significant Accounting Policies.