Doesn't seem to be happening on weekends in May/June. Not bad fares, but closer to $300. Since we have to come from SJC (or SFO) that adds a bit as well.
ITA shows same-day turns at the $179 O fare for several weekends: 5/9, 5/10, 5/17, 5/24, 5/31 (in addition to many weekdays). As filed, it looks like the fare requires travel by 5/31 as OP noted.
Also valid for O/W purchase, fwiw.
ivk5