Preferred Stock Warrants and Common Stock Warrants - Warrants Exercised (Details) - $ / shares		2 Months Ended
	May 08, 2018	Jun. 29, 2018	May 07, 2018
Common stock warrants issued on July 1, 2012
Warrants
Exercise price (in dollars per share)	$ 0.002		$ 0.002
Stock issued upon exercise of warrants (in shares)	485,985
Common stock warrants issued on July 31, 2014, expiring July 2024
Warrants
Exercise price (in dollars per share)		$ 3.02	$ 3.02
Stock issued upon exercise of warrants (in shares)		95,113
Common stock warrants converted from Series D preferred stock warrants issued upon closing of initial public offering
Warrants
Exercise price (in dollars per share)		$ 2.9891
Stock issued upon exercise of warrants (in shares)		130,965