License and Other Revenue - Additional Information (Detail)	1 Months Ended			3 Months Ended
	Jul. 31, 2013 USD ($)	Jun. 30, 2013 USD ($)	Jun. 30, 2013 EUR (€)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2013 EUR (€)
License And Other Revenue [Line Items]
Description of agreement expire term				The agreement will expire at the later of the last-to-expire patent in the EEA or ten years from the first commercial sale of the test in the EEA, which occurred in 2014.
Common stock value				$ 35,000		$ 29,000
Upfront cash payment		$ 408,000	€ 387,500
Revenues and royalties recognized				10,000	$ 0
Royalty revenues				100,000	$ 0
Royalty revenues receivable balance				$ 0		$ 0
Diaxonhit [Member]
License And Other Revenue [Line Items]
Common stock value		$ 476,000					€ 387,500
Shares sold for consideration	$ 467,000