2018 Acquisition
Wombat Security Technologies, Inc.
On February 28, 2018 (the “Wombat Acquisition Date”), pursuant to the terms of the merger agreement, the Company acquired all shares of Wombat Security Technologies, Inc. (“Wombat”), a leader for phishing simulation and security awareness computer-based training. By collecting data from Wombat’s PhishAlarm solution, the Company has access to data on phishing campaigns as seen by non-Company customers, providing broader visibility and insight to the Proofpoint Nexus platform.
With this acquisition, the Company’s customers can leverage the industry’s first solution combining the Company’s advanced threat protection with Wombat’s phishing simulation and computer-based security awareness training. With the combined solutions, the Company’s customers can:
use real detected phishing attacks for simulations, assessing users based on the threats that are actually targeting them; both investigate and take action on user-reporting phishing, leveraging orchestration and automation to find real attacks, quarantine emails in users’ inboxes, and lock user accounts to limit risk; and train users in the moment immediately after they click for both simulated and real phishing attacks.
The Company also expects to achieve savings in corporate overhead costs for the combined entities. These factors, among others, contributed to a purchase price in excess of the estimated fair value of acquired net identifiable assets and, as a result, goodwill was recorded in connection with the acquisition.
Proofpoint, Inc. Notes to Consolidated Financial Statements (Continued) (dollars and share amounts in thousands, except per share amounts)
At the Wombat Acquisition Date, the consideration transferred was $225,366, net of cash acquired of $13,452.
Per the terms of the merger agreement, unvested in-the-money stock options held by Wombat employees were canceled and paid off using the same amount per option as for the common share less applicable exercise price for each option. The fair value of $1,580 of these unvested options was attributed to pre-combination service and included in consideration transferred. The fair value of unvested options of $1,571 was allocated to post-combination services and expensed in the three months ended March 31, 2018. Also, as part of the merger agreement, 51 shares of the Company’s common stock were deferred for certain key employees with the total fair value of $5,458 (see Note 11 “Equity Award Plans”), which was not included in the purchase price. The deferred shares are subject to forfeiture if employment terminates prior to the lapse of the restrictions, and their fair value is expensed as stock-based compensation expense over the remaining service period.
The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
Table:
 | Fair value | Estimated Useful Life
 |  | (in years)
Current assets | $23,344 | N/A
Fixed assets | 954 | N/A
Customer relationships | 37,800 | 7
Order backlog | 6,800 | 2
Core/developed technology | 35,200 | 4
Trade name | 2,400 | 4
Deferred revenue | (14,700) | N/A
Deferred tax liability, net | (14,725) | N/A
Other liabilities | (1,120) | N/A
Goodwill | 162,865 | Indefinite
 | $238,818 | 


Question: How long is the estimated useful life for the Goodwill?
Answer: Indefinite