Retirement Agreement - Additional Information (Detail)		1 Months Ended			12 Months Ended
	Jan. 19, 2018 USD ($)	Feb. 28, 2018 shares	Jan. 31, 2018 USD ($) shares	Sep. 30, 2017 USD ($)	Dec. 31, 2018	Dec. 31, 2017 USD ($) $ / h shares	Dec. 31, 2012 shares	Apr. 01, 2018 USD ($)
Restricted Stock Units (RSUs) [Member] | LTIP [Member]
Defined Benefit Plan Disclosure [Line Items]
Issuance of shares | shares						1,078,000	978,000
Sirgo Retirement Agreement [Member] | Chief Executive Officer [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash payment paid				$ 800,000
Sirgo Retirement Agreement [Member] | Chief Executive Officer [Member] | LTIP [Member]
Defined Benefit Plan Disclosure [Line Items]
Vesting rights, percentage						100.00%
Change in control period considered after retirement date						12 months
Vasisht Retirement Agreement [Member] | Chief Technology Officer [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash payment granted						$ 330,000
Number of equal installments						2
Retirement agreement description						if a Change of Control (as defined in the Vasisht Employment Agreement) occurs before July 1, 2018, Dr. Vasisht will be entitled to the cash payments provided for in Paragraph 4(d) of the Vasisht Employment Agreement (namely, a cash payment equal to: (A) Dr. Vasisht’s annual base salary plus an amount equal to fifty percent (50%) of his such salary multiplied by (B) 1.5), but less the separation payments made under the Vasisht Retirement Agreement
Consulting rate | $ / h						200
Consulting period						12 months
Vasisht Retirement Agreement [Member] | Chief Technology Officer [Member] | LTIP [Member]
Defined Benefit Plan Disclosure [Line Items]
Vesting rights, percentage						100.00%
Vasisht Retirement Agreement [Member] | Chief Technology Officer [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash payment granted								$ 165,000
Vasisht Retirement Agreement [Member] | Chief Technology Officer [Member] | Scenario, Forecast [Member] | Performance Based Restricted Stock Units Rsu [Member]
Defined Benefit Plan Disclosure [Line Items]
Vesting rights, percentage					60.00%
Vesting rights, percentage forfeited					40.00%
Subsequent Event [Member] | Sirgo Retirement Agreement [Member] | Chief Executive Officer [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash payment paid			$ 800,000
Subsequent Event [Member] | Sirgo Retirement Agreement [Member] | Chief Executive Officer [Member] | Performance Based Restricted Stock Units Rsu [Member]
Defined Benefit Plan Disclosure [Line Items]
Issuance of shares | shares			795,730
Subsequent Event [Member] | Sirgo Retirement Agreement [Member] | Chief Executive Officer [Member] | Time Based Restricted Stock Units R S U [Member]
Defined Benefit Plan Disclosure [Line Items]
Issuance of shares | shares			250,000
Subsequent Event [Member] | Vasisht Retirement Agreement [Member] | Chief Technology Officer [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash payment paid	$ 165,000,000
Cash payment paid for deferred raise	$ 20,000
Subsequent Event [Member] | Vasisht Retirement Agreement [Member] | Chief Technology Officer [Member] | Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Issuance of shares | shares		309,162
Subsequent Event [Member] | Vasisht Retirement Agreement [Member] | Chief Technology Officer [Member] | Restricted Stock Units (RSUs) [Member] | 2017 Equity Award [Member]
Defined Benefit Plan Disclosure [Line Items]
Issuance of shares | shares		198,129