CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Property and equipment:
Gamma Knife, accumulated depreciation	$ 1,412,000	$ 1,097,000
Leasehold improvements, accumulated depreciation	$ 666,000	$ 510,000
STOCKHOLDERS' EQUITY
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	25,000,000	25,000,000
Common stock, shares issued (in shares)	7,797,185	7,797,185
Common stock, shares outstanding (in shares)	7,797,185	7,797,185