Fair value measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of assets and liabilities that are measured at fair value on a recurring basis

The following tables summarize the assets measured at fair value on a recurring basis (in thousands):

	September 30, 2017
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	6,291	$	6,291	$	—	$	—
Money market funds	14,493		14,493		—		—
Total cash and cash equivalents	20,784		20,784		—		—
Short-term investments:
Corporate debt securities	26,050		—		26,050		—
Commercial paper	28,128		—		28,128		—
Total short-term investments	54,178		—		54,178		—
Total	$	74,962	$	20,784	$	54,178	$	—

	December 31, 2016
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	2,728	$	2,728	$	—	$	—
Money market funds	19,655		19,655		—		—
Total cash and cash equivalents	22,383		22,383		—		—
Short-term investments:
Corporate debt securities	20,619		—		20,619		—
Commercial paper	13,732		—		13,732		—
Total short-term investments	34,351		—		34,351		—
Total	$	56,734	$	22,383	$	34,351	$	—