Overall gross profit margin on a GAAP and non-GAAP basis for the first quarter of 2018 was 34%, compared to 40% on a GAAP and non-GAAP basis in the first quarter of 2017.
Operating expenses for the first quarter of 2018 were $51.8 million, compared to $56.1 million in the first quarter of 2017. Non-GAAP operating expenses for the first quarter of 2018 were $48.5 million, compared to $53.3 million in the first quarter of 2017.
As of March 31, 2018, cash, investments and restricted cash totaled $147 million. Working capital at the end of the first quarter was $332 million, compared to $354 million at December 31, 2017.
"We are off to a strong start to the year", stated Peter Ungaro, president and CEO of Cray. "We completed several large acceptances during the first quarter at sites around the world, a few of these ahead of schedule. We had one of our strongest bookings quarters in several years, what we believe is another early sign that our target market is continuing to strengthen. Among these new awards, we were selected by the Japanese National Institutes for Quantum and Radiological Science and Technology to deliver our latest generation XC supercomputer to serve as their new flagship system. These are good examples of our strong competitive position, which is key for us to drive growth in 2018 and beyond."
For 2018, while a wide range of results remains possible, Cray continues to expect revenue to grow in the range of 10-15% over 2017. Revenue is expected to be about $110 million for the second quarter of 2018. For 2018, GAAP and non-GAAP gross margins are expected to be in the low-30% range. Non-GAAP operating expenses for 2018 are expected to be in the range of $190 million. For 2018, non-GAAP adjustments are expected to total about $14 million, driven primarily by share-based compensation. For the year, GAAP operating expenses are anticipated to be about $12 million higher than non-GAAP operating expenses, and GAAP gross profit is expected to be about $2 million lower than non-GAAP gross profit.
Based on this outlook, Cray's effective GAAP and non-GAAP tax rates for 2018 are both expected to be in the low-single digit range, on a percentage basis.
Actual results for any future periods are subject to large fluctuations given the nature of Cray's business.
Recent highlights include the following: