Fair value measurements (Tables)

6 Months Ended

Jun. 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 and liabilities measured at fair value on a recurring basis (in thousands):

	June 30, 2017
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	2,486	$	2,486	$	—	$	—
Money market funds	17,469		17,469		—		—
Total cash and cash equivalents	19,955		19,955		—		—
Short-term investments:
Corporate debt securities	31,290		—		31,290		—
Commercial paper	36,593		—		36,593		—
Total short-term investments	67,883		—		67,883		—
Total	$	87,838	$	19,955	$	67,883	$	—

	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	$	—