of 2006. GAAP gross margins for the three months ended April 30, 2007, were 41.5%, compared to 44.6% for the three months ended April 30, 2006, as a result of increased amortization of purchased technology assets, the step-up in inventory and stock-based compensation.
GAAP operating expenses for the three months ended April 30, 2007, were $72.9 million compared to $37.8 million for the comparable period of 2006. In addition to the effect of the Lipman acquisition and related integration expenses, the Company incurred higher non-cash stock compensation expenses and amortization of purchased intangible assets. Stock based compensation for the three months ended April 30, 2007 was $9.8 million compared to $1.0 million for the comparable period of 2006. This increase was primarily due to the acceleration of the vesting of options of Lipman executives, the increase in the number of option holders following the Lipman acquisition and the grant of performance-based restricted stock units to the Company’s Chief Executive Officer. Amortization of purchased intangible assets for the three months ended April 30, 2007 was $6.1 million compared to $1.2 million for the comparable period of 2006, primarily due to the Lipman acquisition.
EBITDA, as adjusted, margins for the three months ended April 30, 2007, expanded for the eleventh consecutive quarter and reached a record level of 26.3%, compared to the 21.6% recorded in the three months ended April 30, 2006.
GAAP EPS for the three months ended April 30, 2007, was $0.06 per diluted share, compared to $0.22 per diluted share, for the comparable period of fiscal 2006, due to acquisition related non-cash charges, higher stock-based compensation expense primarily related to the Lipman acquisition and to a significantly higher GAAP tax rate driven by an increase in the valuation allowance related to Lipman. Net income, as adjusted, which excludes non-cash acquisition related charges and debt issuance costs, as well as non-cash stock-based compensation expense and Lipman integration costs, for the three months ended April 30, 2007, increased 50% to $0.39 per diluted share,