Seagate's high-flying shares fall after first-quarter results
** Data storage provider Seagate Technology's STX.O shares fell ~6% to $626.32 in extended trading
** STX posts revenue of $4.23 bln for the first quarter, above analysts' average estimate of $4.14 bln, according to data compiled by LSEG
** Co forecasts Q2 revenue of $4.8 billion, plus or minus $100 million, above estimates of $4.32 bln
** Stock has more than doubled so far this year, including a near 6% rise just this week in run-up to results