Sen. Ted Cruz's presidential campaign is capping off 2015 with a spike in fundraising, coinciding with momentum in the polls.

The Texas Republican raised nearly $20 million in the fourth quarter of this year, his campaign confirmed Wednesday. The campaign has raised around $45 million since Cruz launched his White House bid in late March.

In a memo, the Cruz campaign said it has received more than 670,000 donations from over 300,000 donors. And just a month before voting officially starts, the campaign is boasting about its robust team in place in the first four primary and caucus states -- Iowa, New Hampshire, South Carolina. and Nevada. The campaign has county chairmen in place in all 171 counties across those states.

A CBS News battleground tracker survey released earlier this month found Cruz has now risen to first place in Iowa with 40 percent support. Similarly, A Des Moines Register/Bloomberg Politics poll released last month showed that Cruz has moved into first place in Iowa.

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CBS News' Alan He contributed to this report.