To expand on these numbers:
If
one building corresponds to one block as the article/linked video below says then satellite and drone images will immediately show when Tesla starts building up additional battery capacity in Nevada:
Tesla Gigafactory Could Be Over Twice Initially Planned Size | CleanTechnica
Therefore the current GF building will probably only be able to pump out 5-7 GWh on the cell/pack level in 2017.
This very roughly corresponds to Tesla and Panasonic only investing about 20% (of the total planned funding of $4-5bn by 2020) until 2017 (that's even generously rounding up past and projected cap-ex for the GF).
The next 10-Q will show how much has been spent on just the first block (corresponding to about 14% of capacity in all 7 blocks) so far.
I know this info isn't new, the video in question has been discussed before:
Tesla Gigafactory - Page 53
But this topic is interesting because of the total investment needed for the GF (to one day build 500k car batteries/year) versus money raised and invested up to now.
Tesla can probably only equip about 70-100k* cars/year (which limits future Model3 sales, this production ceiling can't be changed overnight until new blocks are constructed) using the current block 1 building.
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* I'm likely
very generous with 100k cars/year (because Tesla was talking about 35GWh on cell level and 50GWh on pack level once full output is reached and pack sizes per car keep going up in the future; also, in case assembled cells arrive from third parties into the GF Tesla won't have the full claimed cost advantages over other suppliers...).