GAAP gross profit for the first quarter 2016 was $64.2 million, or 28.8 percent of revenue, including $3.1 million inventory valuation adjustments related to the Pericom acquisition. Non-GAAP gross profit, excluding the inventory adjustment, was $67.3 million, or 30.2 percent of revenue, compared to 26.5 percent last quarter. GAAP gross profit in the first quarter 2015 was $63.9 million, or 31.0 percent of revenue, and in the fourth quarter 2015 was $53.6 million, or 25.0 percent of revenue. The 370 basis point sequential increase in non-GAAP gross profit margin was due primarily to improved product mix and a full quarter of Pericom.

GAAP operating expenses for the first quarter 2016 were $62.8 million, or 28.2 percent of revenue, and $56.8 million, or 25.5 percent of revenue, on a non-GAAP basis, including $6.0 million of transaction, retention and amortization of acquisition related intangible asset expenses. This compares to GAAP operating expenses of $47.0 million, or 22.8 percent of revenue, in the first quarter 2015 and $60.4 million, or 28.2 percent of revenue, in the fourth quarter 2015.

First quarter 2016 GAAP net loss was $1.7 million, or ($0.04) per share, compared to GAAP net income of $11.1 million, or $0.23 per diluted share, in the first quarter 2015 and GAAP net loss of $4.8 million, or ($0.10) per share, in the fourth quarter 2015.

First quarter 2016 non-GAAP adjusted net income was $5.9 million, or $0.12 per diluted share, which excluded, net of tax, $3.5 million of purchase price accounting costs and $4.1 million of non-cash acquisition-related intangible asset amortization costs. This compares to non-GAAP adjusted net income of $12.7 million, or $0.26 per diluted share, in the first quarter 2015 and $6.7 million, or $0.14 per diluted share, in the fourth quarter 2015.

The following is an unaudited summary reconciliation of GAAP net income to non-GAAP adjusted net income and per share data, net of tax (in thousands, except per share data):