Ames-based software company Workiva announced that Matt Rizai has resigned from his positions as chairman and CEO, and that its board has unanimously named Martin Vanderploeg as CEO. Vanderploeg continues as the company’s president and a member of the board. The board also elected David Mulcahy as non-executive chairman. Both appointments, effective immediately, follow a mutual decision between the board and Rizai, the company said in a release. “We thank Matt for his contributions over the past 10 years, as both a co-founder and a leader who helped build and scale the company,” Mulcahy said in a statement. “The progress we’ve made during Matt’s tenure has laid the foundation for our future growth and success.” Workiva on May 2 reported a first-quarter net loss of $9.6 million, compared with a net loss of $5.8 million for the prior year’s first quarter. The company on Monday reaffirmed its second-quarter and full-year 2018 revenue guidance and said it plans to update its previously issued guidance on losses to reflect the impact of separation payments to Rizai when it reports second-quarter financial results in early August.