Organization and Description of Business	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Organization and Description of Business	Organization and Description of BusinessAppian Corporation (together with its subsidiaries, “Appian,” the “Company,” “we” or “our”) provides a low-code automation platform that accelerates the creation of high-impact business applications, enabling our customers to automate the most important aspects of their business. Global organizations use our applications to improve customer experience, achieve operational excellence and simplify global risk management and compliance. We were incorporated in the state of Delaware in August 1999. We are headquartered in Tysons, Virginia and operate in Canada, Switzerland, the United Kingdom, France, Germany, the Netherlands, Italy, Australia, Spain, Singapore and Sweden.