FAIR VALUE MEASUREMENTS (Tables)

3 Months Ended

Mar. 31, 2017

FAIR VALUE MEASUREMENTS

Summary of the levels of the fair value hierarchy into which the Company's financial assets fall

The following table summarizes the levels of the fair value hierarchy into which the Company’s financial assets fall as of March 31, 2017:

	Total		Level 1		Level 2		Level 3
Financial assets:
Included in cash and cash equivalents
Government securities money market	$	116,143	$	—	$	116,143	$	—
Investments
U.S. treasury bills		27,957		27,957		—		—
Common stock		263		263		—		—
Total financial assets	$	144,363	$	28,220	$	116,143	$	—

The following table summarizes the levels of the fair value hierarchy into which the Company’s financial assets fall as of December 31, 2016:

	Total		Level 1		Level 2		Level 3
Financial assets:
Included in cash and cash equivalents
U.S. treasury bills	$	44,999	$	—	$	44,999	$	—
Government securities money market		201,934		—		201,934		—
Investments
U.S. treasury bills		32,995		—		32,995		—
Convertible notes		388		388		—		—
Total financial assets	$	280,316	$	388	$	279,928	$	—