INCOME TAXES	9 Months Ended
Sep. 30, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	16. 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. For the three and nine months ended September 30, 2017, the Company recorded an income tax expense of $2.0 million and $3.9 million, respectively, representing an effective tax rate of 4.4% and 17.1%, respectively. The Company’s estimated annual effective tax rate is lower than the federal statutory rate due to the jurisdictional mix of earnings and the release of valuation allowance against its federal and state tax attributes which can be used to offset current year earnings. For the three and nine months ended September 30, 2016, the Company did not record any income tax expense or benefit. The increase in the income tax expense liability as of September 30, 2017 as compared to the balance as of December 31, 2016 was 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 domestic 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.

16. 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.

For the three and nine months ended September 30, 2017, the Company recorded an income tax expense of $2.0 million and $3.9 million, respectively, representing an effective tax rate of 4.4% and 17.1%, respectively. The Company’s estimated annual effective tax rate is lower than the federal statutory rate due to the jurisdictional mix of earnings and the release of valuation allowance against its federal and state tax attributes which can be used to offset current year earnings. For the three and nine months ended September 30, 2016, the Company did not record any income tax expense or benefit. The increase in the income tax expense liability as of September 30, 2017 as compared to the balance as of December 31, 2016 was 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 domestic 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.