Spending money while building out your main product pipeline is perfectly acceptable to me. How many quarters of runway would you want them to hold on hand? If in six months when their cash on hand gets low they can issue a new round of funding and investors can decide if its worth pumping more money into the company or if they won't be able to turn a profit. This would be the exact behavior you get from any company in a high growth phase, the only difference is most of the time the only people who get a look at the books of these companies are the investment firms who lead crazy valuation rounds since the public doesn't have access to pre IPO startups.