Business Combinations Acquisition of The Email Laundry On October 20, 2017, we acquired all of the outstanding shares of The Email Laundry, a privately held email security company, which is expected to enhance our current email offerings. In connection with this acquisition, we paid cash consideration of $ 4.3 million and issued 259,425 shares of our common stock with an estimated fair value of $ 4.4 million , resulting in total purchase consideration of $ 8.7 million . The purchase price is subject to customary working capital and related adjustments. The purchase price was allocated to intangible assets of $ 2.7 million , goodwill of $ 6.4 million and tangible net liabilities of $ 0.3 million . The intangible assets are composed of technology and customer relationships, each with an estimated weighted average useful life of 3 years. The goodwill is primarily attributable to the know-how of the workforce and is not expected to be deductible for U.S. federal income tax purposes. The results of operations of The Email Laundry have been included in our consolidated statements of operations from the acquisition date. Pro forma financial information has not been presented for this acquisition as the impact to our consolidated financial statements was not material. Acquisition of X15 Software On January 11, 2018, we acquired all of the outstanding shares of privately held X15, a data management company. We expect that the X15 technology will be incorporated into the foundation for our platform and analytics capabilities going forward. In connection with this acquisition, we paid cash consideration of $5.3 million and issued 1,016,334 shares of our common stock with an estimated fair value of $15.4 million , resulting in total purchase consideration of $20.7 million . The purchase price was allocated to intangible assets of $6.1 million , goodwill of $15.3 million and tangible net liabilities of $0.7 million . The intangible asset relates to developed technology with an estimated weighted average useful life of 3 years