Campo input text width: 100%

<table id="gridview" class="gridview" width="50%" cellpadding="0" cellspacing="0"><thead><tr><td style="width: 25%;" id="cod_cliente" class="cellHeader">Cod. Cliente<img src="img/gridView/filter.png" onclick="$(this).typeFilter(jQuery(this).position().top, jQuery(this).position().left);" style="float: right; cursor: pointer;" alt=""></td><td style="width: 50%;" id="nome_cliente" class="cellHeader">Nome do Cliente<img src="img/gridView/filter.png" onclick="$(this).typeFilter(jQuery(this).position().top, jQuery(this).position().left);" style="float: right; cursor: pointer;" alt=""></td><td style="width: 25%;" id="cpf_cliente" class="cellHeader">CPF<img src="img/gridView/filter.png" onclick="$(this).typeFilter(jQuery(this).position().top, jQuery(this).position().left);" style="float: right; cursor: pointer;" alt=""></td></tr><tr><td class="cellFilter"><div style="margin-left: 2px;"><input class="fieldFilter" valuefilter="0" type="text" id="txt_0" onkeyup="$(txt_0).filter(this, 'event');"></div></td><td class="cellFilter"><div style="margin-left: 2px;"><input class="fieldFilter" valuefilter="0" type="text" id="txt_1" onkeyup="$(txt_1).filter(this, 'event');"></div></td><td class="cellFilter"><div style="margin-left: 2px;"><input class="fieldFilter" valuefilter="0" type="text" id="txt_2" onkeyup="$(txt_2).filter(this, 'event');"></div></td></tr></thead><tbody><tr><td id="cod_cliente" class="cellRow">1</td><td id="nome_cliente" class="cellRow">Rafael Fernandes D Orazio</td><td id="cpf_cliente" class="cellRow">352.682.158-40</td></tr><tr><td id="cod_cliente" class="cellRow">2</td><td id="nome_cliente" class="cellRow">Teste</td><td id="cpf_cliente" class="cellRow">053.861.388-20</td></tr><tr><td id="cod_cliente" class="cellRow">3</td><td id="nome_cliente" class="cellRow">Janio Fernandes D Orazio</td><td id="cpf_cliente" class="cellRow">302.632.158-50</td></tr></tbody></table>

o campo text da td do nome não fica 100% , pq ?