Yes, you can save your work and come back and finish your return later. Just click My Account (top right of your screen) then click Save & Sign Out. TurboTax will save your work and sign you out of your account. When you are ready to resume, just sign in using your user id and password
If you need time beyond the filing deadline (April 18, 2017), you can file an extension. Keep in mind that it is an extension of time to file your return, not an extension of time to pay any taxes due. See the FAQ below for more information.
How do I file an IRS extension (Form 4868) in TurboTax Online? https://ttlc.intuit.com/replies/3301811
