In 2000 the band released an independent EP entitled Extendemo, which resulted in their signing to Dreamworks Records in early 2001. Shortly thereafter, the band entered the studio with Don Gilmore, who produced their self-titled major-label debut EP, and their full-length debut, Topsy-Turvy, which were released on October 9, 2001 and April 2, 2002, respectively.

The band toured for a good portion of the next few years in support of their debut album, first playing Vans Warped Tour and co-headlining MTV2's Tour with Lostprophets in 2001. In the summer of 2002, the band played on the second stage of Ozzfest.

Later in 2002, The Apex Theory parted ways with original vocalist due to differences in musical opinions. Khachaturian is currently involved in a solo project and a band dubbed VoKee. The 3 members decided to continue as a three-piece outfit, with guitarist Art Karamian taking responsibility for vocal duties as well.

The Apex Theory officially resurfaced in 2003, self-releasing their latest EP, inthatskyissomethingwatching. Though the band has not embarked on a national tour as of yet, they have successfully played countless shows in their home state of California, as well as in Oregon and Washington.

On June 30, 2006, the band announced the completion of their first full-length album without their former vocalist, Khatchaturian, to be released in Summer of 2007. The album will be titled Faces. The band later decided to postpone the album's release in order to release a one-track EP, entitled Lightpost, on January 16, 2007 via iTunes. The album's only track, "Lightpost", is 15 minutes and 25 seconds long.

In December 2007, the band officially changed its name from Apex Theory to Mt. Helium with the release of their album, Faces. (Wikipedia)