Grant Revenues	12 Months Ended
Dec. 31, 2017
Grant Revenues [Abstract]
Grant Revenues	8. Grant Revenues In June 2015, the Company entered into a Cancer Research Grant Contract (“Grant Contract”) with CPRIT, under which CPRIT awarded a grant not to exceed $19.8 million for use in developing cancer treatments by exploiting the metabolism of cancer cells. The Grant Contract covers a four-year period from June 1, 2014 through May 31, 2018. Upon commercialization of the product, the terms of the Grant Contract require the Company to pay tiered royalties in the low to mid-single digit percentages. Such royalties reduce to less than one percent after a mid-single-digit multiple of the grant funds have been paid to CPRIT as royalties. The agreement includes reimbursement for qualified expenditures incurred and recognized in 2014. Upon execution of the Grant Contract, grant revenue was recognized for the accumulated qualified expenditures paid and recognized in the period from June 1, 2014 through June 30, 2015. For the years ended December 31, 2017, 2016, and 2015 the Company recognized $5.2 million, $4.6 million, and $6.1 million, respectively, in grant revenues for qualified expenditures under the grant. As of December 31, 2017 and 2016, the Company had an outstanding grant receivable of $3.1 million and $1.2 million, respectively, for the grant expenditures that were paid but had not been reimbursed and deferred revenue of $20,000 and $71,000, respectively, for proceeds received but for which the costs had not been incurred or the conditions of the award had not been met.

8. Grant Revenues

In June 2015, the Company entered into a Cancer Research Grant Contract (“Grant Contract”) with CPRIT, under which CPRIT awarded a grant not to exceed $19.8 million for use in developing cancer treatments by exploiting the metabolism of cancer cells. The Grant Contract covers a four-year period from June 1, 2014 through May 31, 2018.

Upon commercialization of the product, the terms of the Grant Contract require the Company to pay tiered royalties in the low to mid-single digit percentages. Such royalties reduce to less than one percent after a mid-single-digit multiple of the grant funds have been paid to CPRIT as royalties.

The agreement includes reimbursement for qualified expenditures incurred and recognized in 2014. Upon execution of the Grant Contract, grant revenue was recognized for the accumulated qualified expenditures paid and recognized in the period from June 1, 2014 through June 30, 2015.

For the years ended December 31, 2017, 2016, and 2015 the Company recognized $5.2 million, $4.6 million, and $6.1 million, respectively, in grant revenues for qualified expenditures under the grant. As of December 31, 2017 and 2016, the Company had an outstanding grant receivable of $3.1 million and $1.2 million, respectively, for the grant expenditures that were paid but had not been reimbursed and deferred revenue of $20,000 and $71,000, respectively, for proceeds received but for which the costs had not been incurred or the conditions of the award had not been met.