A biopsy device comprises a targeting set, a probe assembly, and a holster assembly, which are detachable from one another. The targeting set comprises a needle assembly having a tissue piercing tip, a tissue receiving aperture, and fluid sealing mechanisms. The probe assembly comprises a tissue cutter, a variable external helix, a body, and telescopic cutter cover. The helix may partially retract the cutter within the probe assembly, while a portion of the cutter extends distally from the probe body. The telescopic cutter cover extends from the distal portion of the probe assembly when the probe assembly is detached from the needle assembly. This extension of the telescopic cutter cover shields a user of the biopsy device from the sharp cutter. The telescopic cutter cover further retracts into the probe assembly when the probe assembly is coupled with the needle assembly of the targeting set assembly.