I'd be very surprised if shares haven't already been drawn down...

I'd be very surprised if shares haven't already been drawn down from the 15 million shares given to ATM as 'security'.
I imagine their agreement involves a limit on the rate at which GLN can issue stock to ATM, perhaps $1 million a week. This would allow ATM to sell off their stock piece-by-piece. The last thing ATM would want is to get the entire amount in one big batch at 10% discount to the recent stock price. i.e. it would be very hard to sell out at a profit, which is their business model.
I actually hope the process has already started; otherwise, the declines in share price we've seen can only be explained by other stockholders who are selling in anticipation of ATM getting stock from GLN.