A search of "camtasia license agreement" found "END-USER LICENSE AGREEMENT FOR TECHSMITH SOFTWARE - CAMTASIA®" which states; emphasis mine.
Provided that you comply with all the terms and conditions of this EULA and when required by the Software, you present a valid, authorized, and activated Software key, you may also install and run a second copy of the Software on a second licensed device for use only by you for your internal business or individual use only, whichever is applicable. Only one person at a time may use the Software on each licensed device and the two licensed devices may not be used simultaneously by that one person.
So, no. It can be installed on two computers but only one can legally be used at a time.
