INCOME TAXES	6 Months Ended
Jun. 30, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	13. INCOME TAXES The Company’s tax provision for interim periods is typically determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate, and if the estimated annual tax rate changes, the Company makes a cumulative adjustment in that quarter. The Company computed its tax provision for the six months ended June 30, 2017 based upon the year-to-date effective tax rate as opposed to an estimated annual effective tax rate. The Company concluded that the year-to-date effective tax rate is the most appropriate method to use for the six months ended June 30, 2017, given a reliable estimate of the annual effective tax rate cannot be made. For the three and six months ended June 30, 2017, the Company recorded an income tax benefit of $0.1 million and income tax expense of $1.9 million, respectively. For the three and six months ended June 30, 2016, the Company did not record any income tax expense or benefit. The effective tax rates for the six months ended June 30, 2017 and 2016 are 2.3% and 0%, respectively. The increase in the income tax expense liability as of June 30, 2017 as compared to the balance as of December 31, 2016 is due to additional state and federal income taxes payable as a result of the increase in the amount of income before income taxes. The increase in income is primarily attributable to the gain on the sale of the Company’s PRV to Gilead for $125.0 million in cash during the period ended March 31, 2017.

13. INCOME TAXES

The Company’s tax provision for interim periods is typically determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate, and if the estimated annual tax rate changes, the Company makes a cumulative adjustment in that quarter. The Company computed its tax provision for the six months ended June 30, 2017 based upon the year-to-date effective tax rate as opposed to an estimated annual effective tax rate. The Company concluded that the year-to-date effective tax rate is the most appropriate method to use for the six months ended June 30, 2017, given a reliable estimate of the annual effective tax rate cannot be made.

For the three and six months ended June 30, 2017, the Company recorded an income tax benefit of $0.1 million and income tax expense of $1.9 million, respectively. For the three and six months ended June 30, 2016, the Company did not record any income tax expense or benefit. The effective tax rates for the six months ended June 30, 2017 and 2016 are 2.3% and 0%, respectively. The increase in the income tax expense liability as of June 30, 2017 as compared to the balance as of December 31, 2016 is due to additional state and federal income taxes payable as a result of the increase in the amount of income before income taxes. The increase in income is primarily attributable to the gain on the sale of the Company’s PRV to Gilead for $125.0 million in cash during the period ended March 31, 2017.